Difference between revisions of "Non-malignant skin disease"

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'''Non-malignant skin disease''' is relatively common.  The pathology may or may not be specific.  Some diseases require clinical information to diagnose.
'''Non-malignant skin disease''' is relatively common.  The pathology may or may not be specific.  Some diseases require clinical information to diagnose.  


An introduction to dermatopathology is in the ''[[dermatopathology]]'' article.  [[Nevi]] (moles) and other melanocytic lesions are dealt with in the article ''[[melanocytic lesions]]''.  Inflammatory skin conditions are dealt with in ''[[inflammatory skin disorders]]''.
An introduction to dermatopathology is in the ''[[dermatopathology]]'' article.  [[Nevi]] (moles) and other melanocytic lesions are dealt with in the article ''[[melanocytic lesions]]''.  Inflammatory skin conditions are dealt with in ''[[inflammatory skin disorders]]''.


=Other=
=Other=
==Squamous cell hyperplasia==
==Lichen simplex chronicus==
*[[AKA]] ''lichen simplex chronicus'',<ref name=Ref_PBoD1011>{{Ref PBoD8|1011}}</ref> abbreviated ''LSC''.
{{Main|Lichen simplex chronicus}}


==Prurigo nodularis==
*Abbreviated ''PN''.
*[[AKA]] ''chronic prurigo'' and ''picker nodule''.<ref name=Ref_Derm26>{{Ref Derm|26}}</ref>
===General===
===General===
*Variant of ''spongiotic dermatitis''.<ref name=Ref_DCHH296>{{Ref DCHH|296}}</ref>
*Can be thought of as a localized/focal version of [[lichen simplex chronicus]] (LSC).


Etiology:<ref>URL: [http://emedicine.medscape.com/article/1123423-overview http://emedicine.medscape.com/article/1123423-overview]. Accessed on: 20 August 2010.</ref>
===Gross===
*Pruritus (itchness) -> mechanical trauma -> lichenification (thickened/leathery<ref>URL: [http://www.medterms.com/script/main/art.asp?articlekey=10131 http://www.medterms.com/script/main/art.asp?articlekey=10131]. Accessed on: 20 August 2010.</ref>.
*Dome-shaped/raised - papular (<1 cm) ''or'' nodular (>1 cm).<ref>URL: [http://www.pediatrics.wisc.edu/education/derm/text.html http://www.pediatrics.wisc.edu/education/derm/text.html]. Accessed on: 23 August 2012.</ref>


===Microscopic===
===Microscopic===
Features:<ref name=Ref_PBoD1065-6>{{Ref PBoD|1065-6}}</ref>
*See ''[[lichen simplex chronicus]]''.
*Acanthosis (epithelial thickening).  
 
*Hyperkeratosis.
DDx:
Other features:<ref>URL: [http://emedicine.medscape.com/article/1123423-diagnosis http://emedicine.medscape.com/article/1123423-diagnosis]. Accessed on: 20 August 2010.</ref>
*[[Lichen simplex chronicus]] - a more diffuse process, not a raised lesion.
*Spongiosis (epidermal intercellular edema -- cells appear to have a clear halo around 'em).
*Parakeratosis = retention of nuclei in the stratum corneum.


Images:
===Sign out===
*[http://commons.wikimedia.org/w/index.php?title=File:Lichen_simplex_chronicus_-_low_mag.jpg LSC - low mag. (WC)].
<pre>
*[http://commons.wikimedia.org/w/index.php?title=File:Lichen_simplex_chronicus_-_high_mag.jpg LSC - high mag. (WC)].
SKIN LESION, LEFT CHIN, BIOPSY:  
- PRURIGO NODULARIS.
</pre>
 
====Micro====
The sections show a raised lesion with compact hyperkeratosis and irregular acanthosis. Spongiosis is seen focally. There is minimal hypergranulosis.
 
There is no thinning of the suprapapillary plate and no dilated superficial blood vessels. There is no interface activity.


=Very common=
=Very common=
==Dermatophytosis==
==Dermatomycosis==
:''Dermatophytosis'' redirects here.
===General===
===General===
*[[microorganisms|Fungal infection]] of skin.
*[[microorganisms|Fungal infection]] of skin.
Note:
*''Dermatophytosis'' (ring worm) is a type of dermatomycosis.


===Microscopic===
===Microscopic===
Line 34: Line 46:
*Microorganisms - '''key feature'''.
*Microorganisms - '''key feature'''.
**Often hyphae (candida) - like twigs of a tree... branching.
**Often hyphae (candida) - like twigs of a tree... branching.
*Perivascular inflammation.
***May be very fragmented in section ~ size of a neutrophil.
*Exocytosis - blood cell infiltrate the epidermis.
*Perivascular inflammation, esp. neutrophils.
*[[Exocytosis]] - blood cell infiltrate the epidermis.
 
====Images====
<gallery>
Image:Dermatomycosis_-_intermed_mag.jpg | Dermatomycosis - intermed. mag. (WC)
Image:Dermatomycosis_-_high_mag.jpg | Dermatomycosis - high mag. (WC)
Image:Dermatomycosis_-_gms_-_low_mag.jpg | Dermatomycosis - GMS stain - low mag. (WC)
Image:Dermatomycosis_-_gms_-_high_mag.jpg | Dermatomycosis - GMS stain - high mag. (WC)
</gallery>
www:
*[http://missinglink.ucsf.edu/lm/DermatologyGlossary/img/Dermatology%20Glossary/Glossary%20Histo%20Images/tinea_pas.jpg Dermatophytosis (ucsf.edu)].<ref>URL: [http://missinglink.ucsf.edu/lm/DermatologyGlossary/tinea.html http://missinglink.ucsf.edu/lm/DermatologyGlossary/tinea.html]. Accessed on: 25 February 2013.</ref>


===Stains===
===Stains===
*[[GMS]].
*[[GMS stain]].
*[[PAS]].
*[[PAS-D stain]].


==Cicatrix==
===Sign out===
*[[AKA]] ''scar''.
<pre>
===General===
SKIN, BIOPSY:
*Previous surgery, biopsy, trauma.
- SKIN WITH SUPERFICIAL FUNGAL ORGANISMS CONSISTENT WITH CANDIDA.
- REACTIVE CHANGES OF THE EPITHELIUM.
</pre>
 
====Micro====
The sections show skin with a neutrophilic infiltrate in the superficial epidermis.  PAS-D staining demonstrates fungal organisms with a morphology suggestive of candida.


===Microscopic===
The epithelium has parakeratosis, acanthosis and spongiosis. No mitotic activity is appreciated. The keratinocytes are moderately enlarged and have evident nucleoli.
Features:
*Loss of adnexal structures.
*Dense collagen - fibers run parallel to the dermal-epidermal (DE) junction.
*Loss of dermal papilla.


Image:
==Cicatrix==
*[http://commons.wikimedia.org/wiki/File:ScarHistology.JPG Scar (WC)].
{{Main|Dermal scar}}


==Fibroepithelial polyp==
==Fibroepithelial polyp==
*[[AKA]] ''acrochordon'', ''skin tag''.
{{Main|Fibroepithelial polyp}}
===General===
*Benign.
*Older people.
*May be associated with pregnancy, diabetes, intestinal polyposis.<ref name=Ref_PCPBoD8|596>{{Ref PCPBoD8|596}}</ref>


===Gross===
==Actinic keratosis==
*Raised skin-coloured lesion.
{{Main|Actinic keratosis}}


Image:
==Actinic cheilitis==
*[http://commons.wikimedia.org/wiki/File:Skintagblemish.jpg Skin tag (WC)].
===General===
*[[Actinic keratosis]] of the lip.<ref name=pmid3305604>{{Cite journal  | last1 = Picascia | first1 = DD. | last2 = Robinson | first2 = JK. | title = Actinic cheilitis: a review of the etiology, differential diagnosis, and treatment. | journal = J Am Acad Dermatol | volume = 17 | issue = 2 Pt 1 | pages = 255-64 | month = Aug | year = 1987 | doi =  | PMID = 3305604 }}</ref>


===Microscopic===
===Microscopic===
Features:
:See ''[[actinic keratosis]]''.
*On a stalk / epithelium on three sides.
*Benign epidermis.


Image:
===Sign out===
*[http://dermatlas.med.jhmi.edu/derm/IndexDisplay.cfm?ImageID=1767547949 Fibroepithelial polyp (dermatlas.med.jhmi.edu)].<ref>URL: [http://dermatlas.med.jhmi.edu/derm/result.cfm?Diagnosis=1196583692 http://dermatlas.med.jhmi.edu/derm/result.cfm?Diagnosis=1196583692]. Accessed on: 1 September 2011.</ref>
<pre>
LESION, LOWER LIP, BIOPSY:  
- ACTINIC CHEILITIS.
- SOLAR ELASTOSIS.
</pre>


==Actinic keratosis==
====Micro====
*AKA solar keratosis. (???)
The sections show skin with moderate basal nuclear hyperchromasia and atypia, and parakeratosis. The squamous epithelium has maturation to the surface.  There is no inflammation at the dermal-epidermal interface. Solar elastosis is present.
===General===
Clinical: yellow-brown scaly, patches, sandpaper sensation.


Risk factors:<ref name=Ref_PBoD8_1180>{{Ref PBoD8|1180}}</ref>
==Seborrheic keratosis==
*Sun exposure.
{{Main|Seborrheic keratosis}}
*Immune suppression (e.g. organ transplant recipients).


===Microscopic===
==Pilomatricoma==
Features:<ref>URL: [http://emedicine.medscape.com/article/1099775-workup#a0723 http://emedicine.medscape.com/article/1099775-workup#a0723]. Accessed on: 1 September 2011.</ref>
{{Main|Pilomatricoma}}
*Epidermal nuclear atypia:
**Variation is size, shape and staining.
***Nuclear enlargement - '''key feature'''.
****Should involve the basal layer.
*Abnormal epidermal architecture:
**Pallisading. (???)
*+/-Parakeratosis.
*+/-Irregular acanthosis.


Image:
==Dermatofibroma==
*[http://commons.wikimedia.org/wiki/File:Actinic_Keratosis,_H%26E.jpg Actinic keratosis (WC)].
{{Main|Dermatofibroma}}


==Seborrheic keratosis==
==Ezcema==
*Abbreviated ''SK''.
===General===
===General===
*Benign.
*A nebulous thingy.
*Most common tumour in older people.<ref name=emed_sk2>URL: [http://emedicine.medscape.com/article/1059477-overview#a0199 http://emedicine.medscape.com/article/1059477-overview#a0199]. Accessed on: 26 August 2011.</ref>
*Very common.
*"Large number" of SKs = paraneoplastic syndrome (''Leser–Trélat sign'').<ref name=Ref_PCPBoD8_595>{{Ref PCPBoD8|595}}</ref>


Epidemiology:
DDx:
*Old people.
*Contact allergy.
*Usu. in sun exposed area.<ref name=emed_sk1>URL: [http://emedicine.medscape.com/article/1059477-overview http://emedicine.medscape.com/article/1059477-overview]. Accessed on: 26 August 2011.</ref>
*[[Drug reaction]].
 
*Food allergy.
===Gross===
*"Stuck-on" appearance - raised lesion.
 
Image(s):
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=91774460 SK - gross image (dermatlas.org)].


===Microscopic===
===Microscopic===
Features:<ref name=Ref_PCPBoD8_595>{{Ref PCPBoD8|595}}</ref>
Features:<ref>{{Ref PBoD8|1188}}</ref>
*Raised above skin surface.  
*Spongiosis (epidermal edema); keratinocytes spacing increased - '''key feature'''.
*Border sharply demarcated.
*+/-Interdermal vesicles.
*Hyperkeratosis - stratum corneum extra thick.
*+/-Eosinophils (may suggest Rx reaction).
*Horn cysts - intraepidermal collections of keratin.
*Perivascular lymphocytes.
*Clusters of cells with brown granular material in the superficial dermis/dermoepidermal junction - pigmented melanocytes.  


Images:
==Acne vulgaris==
*[http://commons.wikimedia.org/wiki/File:Seborrheic_keratosis_(1).jpg Seborrheic keratosis - low mag. (WC)].
===General===
*[http://commons.wikimedia.org/wiki/File:Seborrheic_keratosis_%282%29.jpg Seborrheic keratosis - high mag. (WC)].
*Extremely common - esp. among adolescents.
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=-1985374774 Seborrheic keratosis - high mag. (dermatlas.org)].
*Very rarely seen by pathologists.
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=-1880960893 Seborrheic keratosis - low mag.  (dermatlas.org)].


==Pilomatricoma==
Treatments:
*[[AKA]] ''calcifying epithelioma of Malherbe''<ref>{{Ref Derm|387}}</ref>, [[AKA]] ''pilomatrixoma''.
*Antibiotic (minocycline).
===General===
*Isotretinoin [[AKA]] all-trans retinoic acid (ATRA).
*Benign skin tumour.
*Most common solid skin tumour of children.<ref name=emed1058965>URL: [http://emedicine.medscape.com/article/1058965-overview http://emedicine.medscape.com/article/1058965-overview]. Accessed on: 10 September 2011.</ref>
*CTNNB1 gene mutation important in pathogenesis.<ref name=Ref_PCPBoD8_597>{{Ref PCPBoD8|597}}</ref>


Clinical:
===Gross===
*Hard nodule - calcification.
*Papules, pustules, nodules or cysts.
*+/-Painful.
**White, black or erythematous.


Treatment:
Images:
*Surgical excision.<ref name=emed1058965>[http://emedicine.medscape.com/article/1058965-overview http://emedicine.medscape.com/article/1058965-overview]</ref>
*[http://commons.wikimedia.org/wiki/File:Blackheads.JPG Blackheads (WC)].


===Microscopic===
===Microscopic===
Features:<ref name=emed1058965dx>URL: [http://emedicine.medscape.com/article/1058965-diagnosis http://emedicine.medscape.com/article/1058965-diagnosis]. Accessed on: 10 September 2011.</ref>
Features:<ref>{{Ref Derm|76}}</ref>
*Lower dermis/subcutaneous adipose lesion; thus, usu. surrounded by connective tissue.
*Folliculitis:<ref name=Ref_Derm77>{{Ref Derm|77}}</ref>
**Sharpy demarcated island of cells.
**[[Neutrophil]]s around hair follicle and infiltrate into it - including the follicular canal.
**Calcification in 75% - with calcium staining (von Kossa).
*Epidermal invagination ''or'' cyst at site of a hair follicle - contains:
*Cells:<ref>[http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ngcase02d.htm http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ngcase02d.htm]</ref>
**Sebum.
**Basaloid epithelial cells - have prominent nucleoli.
**+/-Bacteria (''Propionibacterium acnes'') and inflammatory cells - typically neurophils.
**Anucleate squamous cells ("ghost cells").  
**Giant cell foreign body type [[granulomas]] (form in reaction to keratin).


Notes:
Subtyped into:
*Keratin a prominent feature on cytology - lots of orange stuff.
#Open comedones ("blackheads") - no extension to epidermal surface.
#Closed comedones ("whiteheads") - to epidermal surface have wide opening.


Images:
DDx - acneiform disorder:<ref name=Ref_Derm77>{{Ref Derm|77}}</ref>
*[http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ngcase02.htm Pilomatrixoma - cytology (bccancer.bc.ca)].
*[[Rosacea]].
*[http://www.dermrounds.com/photo/1980062:Photo:431 Pilomatrixoma - histology (dermrounds.com)].
*Infective folliculitis.
*[http://en.wikipedia.org/wiki/File:Pilomatrixoma_-_high_mag.jpg Pilomatrixoma - high mag. (WC)].
*Perioral dermatitis.
*[http://en.wikipedia.org/wiki/File:Pilomatrixoma_-_intermed_mag.jpg Pilomatrixoma - intermed. mag. (WC)].
*Acne vulgaris.


DDx:
Image:
*[[Epidermal inclusion cyst]].
*[http://www.dermnet.com/images/Acne-Histology/picture/4069 Acne (dermnet.com)].


==Dermatofibroma==
==Solar elastosis==
*Abbreviated ''DF''.
*[[AKA]] ''actinic elastosis''.<ref>URL: [http://www.dermnetnz.org/dermal-infiltrative/solar-elastosis.html http://www.dermnetnz.org/dermal-infiltrative/solar-elastosis.html]. Accessed on: 27 March 2013.</ref>
===General===
===General===
*AKA ''fibrous histiocytoma''.
*Very common.
*Reactive process -- it is ''not'' a neoplasm.
*Caused by sun exposure - specifically UV light.<ref name=pmid20802019>{{Cite journal  | last1 = Thomas | first1 = NE. | last2 = Kricker | first2 = A. | last3 = From | first3 = L. | last4 = Busam | first4 = K. | last5 = Millikan | first5 = RC. | last6 = Ritchey | first6 = ME. | last7 = Armstrong | first7 = BK. | last8 = Lee-Taylor | first8 = J. | last9 = Marrett | first9 = LD. | title = Associations of cumulative sun exposure and phenotypic characteristics with histologic solar elastosis. | journal = Cancer Epidemiol Biomarkers Prev | volume = 19 | issue = 11 | pages = 2932-41 | month = Nov | year = 2010 | doi = 10.1158/1055-9965.EPI-10-0686 | PMID = 20802019 }}</ref>
*Usually associated with previous trauma.
**Severity correlated with cumulative exposure to UV light..<ref name=pmid17204514/>
**In women... usually legs.
*Often co-localized with skin cancers - as UV light is risk factor for skin cancers.<ref name=pmid17204514 >{{Cite journal  | last1 = Karagas | first1 = MR. | last2 = Zens | first2 = MS. | last3 = Nelson | first3 = HH. | last4 = Mabuchi | first4 = K. | last5 = Perry | first5 = AE. | last6 = Stukel | first6 = TA. | last7 = Mott | first7 = LA. | last8 = Andrew | first8 = AS. | last9 = Applebaum | first9 = KM. | title = Measures of cumulative exposure from a standardized sun exposure history questionnaire: a comparison with histologic assessment of solar skin damage. | journal = Am J Epidemiol | volume = 165 | issue = 6 | pages = 719-26 | month = Mar | year = 2007 | doi = 10.1093/aje/kwk055 | PMID = 17204514 }}</ref>
*Benign.


===Microscopic===
===Microscopic===
Features:<ref name=Ref_WMSP492>{{Ref WMSP|492}}</ref>
Features:
*Prominent fibrous bundles, especially at the edge of the lesion.
*Grey, spaghetti-like material in the superficial dermis.
**Surrounded by spindle cells (fibroblasts).
 
***Usually thought of as fibroblasts surrounded by fibrous material ("collagen-trapping").
DDx:
*Lack of adnexal structures, i.e. no sweat glands, no hair.
*[[Actinic keratosis]].
*+/-Epidermal changes - known as "dirty fingers":<ref>BD. 13 April 2011.</ref>
*[[Basal cell carcinoma]].
**Acanthosis (thickened epithelial layer - specifically thickened ''stratum spinosum'').
*[[Squamous cell carcinoma of the skin|Squamous cell carcinoma]].
**Basal keratinocyte hyperpigmentation.


Images:
Note:
*[http://missinglink.ucsf.edu/lm/DermatologyGlossary/dermatofibroma.html Dermatofibroma (ucsf.edu)].
*The DDx above is things associated with sun damaged skin.
*[http://www.pacificderm.org/newsflashcpcapril04.html DF - several images (pacificderm.org)].
*Dermal mucin (as my be seen in [[lupus erythematosus]]) is a possible mimic - but it isn't spaghetti-like and the "background" (an [[interface dermatitis]]) is different.


DDx:
====Images====
*[[Dermatofibrosarcoma protuberans]] (DFSP).
<gallery>
*[[Neurofibroma]].
Image:Solar_elastosis_-_intermed_mag.jpg | Solar elastosis - intermed. mag. (WC)
*[[Blue nevus]].
Image:Solar_elastosis_-_high_mag.jpg | Solar elastosis - high mag. (WC)
*[[Melanoma]].
</gallery>
www:
*[http://dermpathexpert.com/id88.html Solar elastosis - several images (dermpathexpert.com)].


====Subtypes====
===Sign out===
Like all common things... there are subtypes:<ref>{{Ref Sternberg5|51}}</ref>
<pre>
*Cellular.
SKIN, RIGHT CHEEK, RE-EXCISION:
*Deep penetrating.
- DERMAL SCAR.
*Lipidized - with foamy macrophages, hemorrhage and Touton-like giant cells.
- EXTENSIVE SOLAR ELASTOSIS.
*Epithelioid cell histiocytoma.
</pre>
*Fibrotic.
*Aneurysmal - large blood filled + features of ''lipidized''.
*Granular cell dermatofibroma.
*Dermatofibroma with monster cells.


===IHC===
=====Prominent blood vessels=====
Features:<ref name=pmid7694515>{{cite journal |author=Abenoza P, Lillemoe T |title=CD34 and factor XIIIa in the differential diagnosis of dermatofibroma and dermatofibrosarcoma protuberans |journal=Am J Dermatopathol |volume=15 |issue=5 |pages=429–34 |year=1993 |month=October |pmid=7694515 |doi= |url=}}</ref><ref name=pmid9129699>{{cite journal |author=Goldblum JR, Tuthill RJ |title=CD34 and factor-XIIIa immunoreactivity in dermatofibrosarcoma protuberans and dermatofibroma |journal=Am J Dermatopathol |volume=19 |issue=2 |pages=147–53 |year=1997 |month=April |pmid=9129699 |doi= |url=}}</ref>
<pre>
*Factor XIIIa +ve.
SKIN LESION, LEFT CHEEK, BIOPSY:
**Usually negative in [[DFSP]].
- SKIN WITH SOLAR ELASTOSIS AND PROMINENT SMALL BLOOD VESSELS.
*CD34 -ve.
</pre>
**Usually positive in DFSP.
*D2-40 +ve.<ref name=pmid20062007>{{cite journal |author=Bandarchi B, Ma L, Marginean C, Hafezi S, Zubovits J, Rasty G |title=D2-40, a novel immunohistochemical marker in differentiating dermatofibroma from dermatofibrosarcoma protuberans |journal=Mod. Pathol. |volume=23 |issue=3 |pages=434–8 |year=2010 |month=March |pmid=20062007 |doi=10.1038/modpathol.2009.176 |url=}}</ref>
**Usually negative in DFSP.


==Ezcema==
<pre>
===General===
SUPERIOR SHOULDER, LEFT, PUNCH BIOPSY:
*A nebulous thingy.
- BENIGN SKIN WITH MODERATE SOLAR ELASTOSIS, PROMINENT SMALL BLOOD VESSELS AND
*Very common.
  SCATTERED PERIVASCULAR LYMPHOCYTES AND PLASMA CELLS.
- NEGATIVE FOR BASAL CELL CARCINOMA.
- NEGATIVE FOR ACTINIC KERATOSIS.
</pre>


DDx:
====Micro====
*Contact allergy.
The sections show hair bearing skin with solar elastosis and numerous small dilated blood vessels. The dermis is mildly fibrotic. Compact keratin is present.
*Drug reaction.
*Food allergy.


===Microscopic===
The epidermis matures to the surface. A granular layer is present. There is no basal
Features:<ref>{{Ref PBoD8|1188}}</ref>
epidermal atypia. No melanocytic nests are identified. There is no palisading of the basal
*Spongiosis (epidermal edema); keratinocytes spacing increased - '''key feature'''.
cells. Rare scattered lymphocytes are in the dermis.
*+/-Interdermal vesicles.
*+/-Eosinophils (may suggest Rx reaction).
*Perivascular lymphocytes.


=Very common - viral=
=Very common - viral=
==Verruca vulgaris==
==Verruca vulgaris==
===General===
{{Main|Verruca vulgaris}}
*[[AKA]] common wart.
*Etiology - [[HPV]].
 
Notes:
*Related to [[condyloma acuminatum]].
 
===Microscopic===
Features:<ref>URL: [http://missinglink.ucsf.edu/lm/DermatologyGlossary/verruca_vulgaris.html http://missinglink.ucsf.edu/lm/DermatologyGlossary/verruca_vulgaris.html]. Accessed on: 14 July 2010.</ref>
*Hyperkeratosis (more keratin - thick stratum corneum).
*Hypergranulosis (thicker stratum granulosum).
*Acanthosis (thickening of the stratum spinosum).
*Rete ridges lengthened (~7-10x normal).
*Large blood vessels at the dermal-epidermal junction.
 
Memory device: there is more of everything - more s. corneum, s. granulosum, s. spinosum, longer rete ridges, more (larger) blood vessels.
 
Images:
*[http://commons.wikimedia.org/wiki/File:Verruca_vulgaris_-_very_low_mag.jpg Verruca vulgaris - very low mag. (WC)].
*[http://commons.wikimedia.org/wiki/File:Verruca_vulgaris_-_intermed_mag.jpg Verruca vulgaris - intermed mag. (WC)].


==Verruca plana==
==Verruca plana==
Line 265: Line 238:
*Viral keratohyaline.
*Viral keratohyaline.
*Koilocytes.
*Koilocytes.
*Acanthosis - yet flat surface and base.
*[[Acanthosis]] - yet flat surface and base.


Notes:
Notes:
*It differs from verruca vulgaris... (1) orthokeratosis, (2) flat surface and base.
*It differs from [[verruca vulgaris]]... (1) orthokeratosis, (2) flat surface and base.


=Less common=
=Less common=
==Cutaneous calcinosis==
==Chronic folliculitis==
*[[AKA]] ''calcinosis cutis''.
:''Folliculitis'' redirect here.
===General===
===General===
*Benign in itself; underlying cause may not be benign.
*Common.
*Infrequently biopsied.
 
===Gross===
*Erythema.<ref>URL: [http://www.webmd.com/skin-problems-and-treatments/tc/folliculitis-topic-overview http://www.webmd.com/skin-problems-and-treatments/tc/folliculitis-topic-overview]. Accessed on: 7 November 2012.</ref>


Subtypes:<ref name=emed>URL: [http://emedicine.medscape.com/article/1103137-overview http://emedicine.medscape.com/article/1103137-overview]. Accessed on: 21 September 2011.</ref>
DDx gross:
#Dystrophic - due to death of cells; may be related to a tumour.
*[[Melanocytic lesion]]s.
#Metastatic - due to chronic renal failure; hyperkalemia; paraneoplastic phenomenon.
#Iatrogenic - post surgical.
#Idiopathic.


===Microscopic===
===Microscopic===
Features:
Features:
*Dermal calcification:
*Inflammation around the hair follicle - '''key feature'''.
**Acellular purple blobs on [[H&E]].
**Lymphocytes - usu. predominant.
***+/-Artefactual tearing of surrounding tissue due to processing (cutting).
*+/-Chronic changes:
***+/-Small artefactual lines ~1-2 micrometers due to processing (cutting).  
**[[Acanthosis]].
**Usu. well-circumscribed.
**Hyperkeratosis.
**Hypergranulosis.


Images:
DDx:
*[http://nelspruit-histopath.blogspot.com/2010/12/skin-calcinosis-cutis.html Calcinosis cutis (blogspot.com)].
*[[Acne vulgaris]].


==Dilated pore of Winer==
===Sign out===
===General===
<pre>
*Benign.
SKIN LESION, UPPER ARM, BIOPSY:
*Looks like zit.
- CHRONIC FOLLICULITIS WITH SECONDARY SURFACE CHANGES.
</pre>


===Microscopic===
====Micro====
Features:<ref name=Ref_WMSP486>{{Ref WMSP|486}}</ref>
The sections show hair-bearing skin with abundant lymphocytes around and within the hair follicle wall.  
*Dilated hair follicle with keratin.
*Acanthosis.
*Budding of epidermis (into dermis).


==Lichenoid keratosis==
The non-hair follicle epidermis has acanthosis, hypergranulosis and compact hyperkeratosis.  There is no inflammatory cell infiltrate in the non-hair follicle epidermis or at the non-hair follicle interface.
===General===
*Caucasians - middle age or older.  


Clinical DDx:<ref name=Ref_Derm346>{{Ref Derm|346}}</ref>
There are no granulomas.
*[[BCC]], [[SCC]], melanocytic neoplasm.


===Microscopic===
==Clear cell acanthoma==
Features:<ref name=Ref_Derm347>{{Ref Derm|347}}</ref>
{{Main|Clear cell acanthoma}}
*Hyperkeratosis.
*Parakeratosis.
*Band of inflammatory cells at DE junction (lichenoid inflammation).
*Dead keratinocytes (Civatte bodies).
*Dermal melanophages.


DDx:
==Chondrodermatitis nodularis chronica helicis==
*[[Lichen planus]] - need clinical correlation (mucosal lesions).
*[[AKA]] ''chondrodermatitis nodularis helicis''.
*Drug reaction.
*Abbreviated ''CNCH''.
*[[Cutaneous T-cell lymphoma]].
*[[AKA]] ''Winkler disease''.<ref>URL: [http://www.head-face-med.com/content/4/1/2 http://www.head-face-med.com/content/4/1/2]. Accessed on: 16 January 2014.</ref>
*Regressed melanocytic lesion.
{{Main|Chondrodermatitis nodularis chronica helicis}}


Images:
==Cutaneous calcinosis==
*[http://www.dermpathexpert.com/id57.html Lichenoid keratosis (dermpathexpert.com)].
*[[AKA]] ''calcinosis cutis''.
{{Main|Cutaneous calcinosis}}


==Granuloma annulare==
==Dilated pore of Winer==
===General===
===General===
*Benign and self-limited condition.
*Benign.
*Etiology unknown - may be assoc. with trauma.<ref name=Ref_Derm51>{{Ref Derm|51}}</ref>
*Looks like a zit.


===Microscopic===
===Microscopic===
Features:<ref name=Ref_WMSP478>{{Ref WMSP|478}}</ref>
Features:<ref name=Ref_WMSP486>{{Ref WMSP|486}}</ref>
*Dermal palisading [[granuloma]] around:
*Dilated hair follicle with keratin.
**Necrotic collagen - '''key feature'''.
*[[Acanthosis]].
***Nuclei "missing" - have undergone karyolysis.
*Budding of epidermis (into dermis).
**Mucin.
***Loose/pale, paucicellular, eosinophilic.
*Chronic inflammatory cells.
 
Notes:
#There may be multiple small foci with intervening normal dermis.<ref name=Ref_Derm51>{{Ref Derm|51}}</ref>
#Granuloma annulare can be subclassified into ''subcutaneous'' and ''interstitial''.
#Histomorphologically similar to ''[[Rheumatoid nodule]].


DDx:
DDx:
*[[Necrobiosis lipoidica]] - little mucin, no normal dermis between foci.<ref name=Ref_Derm51>{{Ref Derm|51}}</ref>
*[[Pilar sheath acanthoma]].
*[[Rheumatoid nodule]].


Images:
Image:
*[http://www.dermaamin.com/site/histopathology-of-the-skin/61-i/1813-interstitial-granuloma-annulare-.html Granuloma annulare (dermaamin.com)].
*[http://dermpathexpert.com/id90.html Dilated pore of Winer (dermpathexpert.com)].


==Necrobiosis lipoidica==
==Lichenoid keratosis==
===General===
*[[AKA]] ''lichen planus-like keratosis''.
Associated with:
{{Main|Lichenoid keratosis}}
*[[Diabetes mellitus]] - known as ''necrobiosis lipoidica diabeticorum''.
*[[Rheumatoid arthritis]].


===Microscopic===
==Granuloma annulare==
Features:<ref name=Ref_Derm51>{{Ref Derm|51}}</ref>
{{Main|Granuloma annulare}}
*Dermal palisading [[granuloma]] around:
**Necrotic collagen - '''key feature'''.
***Nuclei "missing" - have undergone karyolysis.
*Little mucin, no normal dermis between foci.


DDx:
==Necrobiosis lipoidica==
*[[Granuloma annulare]] - more mucin, normal dermis between foci.<ref name=Ref_Derm51>{{Ref Derm|51}}</ref>
{{Main|Necrobiosis lipoidica}}
*[[Rheumatoid nodule]].


==Keloid==
==Keloid==
===General===
{{Main|Keloid}}
*Sites of previous trauma/surgery, esp. in dark skinned individuals.<ref name=Ref_WMSP492>{{Ref WMSP|492}}</ref>


===Microscopic===
==Angiofibroma==
Features:<ref name=Ref_WMSP492>{{Ref WMSP|492}}</ref>
:See also: ''[[nasopharyngeal angiofibroma]]''.
*Thick collagen bundles - surrounded by paler staining fibroblasts - '''key feature'''.
:Should '''not''' be confused with ''[[angiokeratoma]]''.
*Lesion replaces adnexal structures, e.g. hair, sweat glands.
{{Main|Angiofibroma}}
 
DDx:
*Hypertrophic scar.


Images:
==Benign fibrous papule==
*[http://missinglink.ucsf.edu/lm/DermatologyGlossary/keloids.html Keloids (ucsf.edu)].
*[[AKA]] ''fibrous papule''.


==Angiofibroma==
:See also: ''[[nasopharyngeal angiofibroma]]''.
===General===
===General===
*May be seen in the context of [[tuberous sclerosis]] - esp. "butterfly area of the face".<ref name=Ref_WMSP492>{{Ref WMSP|492}}</ref>
*An ''[[angiofibroma]]'' on the face that is solitary.<ref name=Ref_Derm505>{{Ref Derm|505}}</ref><ref name=pmid18032900>{{Cite journal  | last1 = Jacyk | first1 = WK. | last2 = Rütten | first2 = A. | last3 = Requena | first3 = L. | title = Fibrous papule of the face with granular cells. | journal = Dermatology | volume = 216 | issue = 1 | pages = 56-9 | month =  | year = 2008 | doi = 10.1159/000109359 | PMID = 18032900 }}</ref>


Clinical:
===Gross===
*Firm, dome-shaped, flesh coloured.
*Solitary lesion of the face - '''important'''.<ref name=Ref_Derm505>{{Ref Derm|505}}</ref>
**Usually on the nose.<ref name=pmid18032900/>


===Microscopic===
===Microscopic===
Line 400: Line 345:
**Enlarged fibroblasts.
**Enlarged fibroblasts.
*Dilated small vessels.
*Dilated small vessels.
*+/-Multinucleated stromal cells.<ref name=pmid543528>{{Cite journal  | last1 = Ragaz | first1 = A. | last2 = Berezowsky | first2 = V. | title = Fibrous papule of the face. A study of five cases by electron microscopy. | journal = Am J Dermatopathol | volume = 1 | issue = 4 | pages = 353-6 | month =  | year = 1979 | doi =  | PMID = 543528 }}</ref>
*+/-Stellate cells.<ref name=pmid543528/>


Image:
DDx:
*[http://www.drdittmar.lu/images/sce/angiofibroma-s.jpg Angiofibroma (drdittmar.lu)].<ref>URL: [http://www.drdittmar.lu/Services.aspx http://www.drdittmar.lu/Services.aspx]. Accessed on: 1 September 2011.</ref>
*[[Angiofibroma]] - not solitary or not on the nose.


==Molluscum contagiosum==
Note:
===General===
*Several variants exist.<ref name=pmid18032900>{{Cite journal  | last1 = Jacyk | first1 = WK. | last2 = Rütten | first2 = A. | last3 = Requena | first3 = L. | title = Fibrous papule of the face with granular cells. | journal = Dermatology | volume = 216 | issue = 1 | pages = 56-9 | month = | year = 2008 | doi = 10.1159/000109359 | PMID = 18032900 }}</ref>
*Etiology: caused by ''molluscum contagiosum virus''.


===Microscopic===
===Images===
Features:
*[http://www.dermaamin.com/site/histopathology-of-the-skin/58-f/1739-fibrous-papule-angiofibroma-.html Fibrous papule (dermaamin.com)].
*A suprabasilar epidermal lesion consisting of "molluscum bodies", i.e. ''molluscum bodies'' are found above the stratum basale.<ref>[http://www.missionforvisionusa.org/anatomy/2006/08/what-is-molluscum-contagiosum.html http://www.missionforvisionusa.org/anatomy/2006/08/what-is-molluscum-contagiosum.html]</ref>
*Molluscum bodies - '''key feature''':
**Large cells with abundant granular eosinophilic cytoplasm.
**Small peripheral nucleus.


Image(s):
===Sign out===
*[http://commons.wikimedia.org/wiki/File:Molluscum_contagiosum_high_mag.jpg Molluscum contagiosum - high mag. (WC)].
<pre>
*[http://commons.wikimedia.org/wiki/File:Molluscum_contagiosum_low_mag.jpg Molluscum contagiosum - low magnification (WC)].
SKIN LESION, CHIN, BIOPSY:
- BENIGN FIBROUS PAPULE.
</pre>


Notes:
==Molluscum contagiosum==
*Molluscum bodies very vaguely resemble ''[[signet ring cell]]s'' -- but:
{{Main|Molluscum contagiosum}}
**Cytoplasm eosinophilic and granular.
**Nucleus usually smaller than in signet ring cell.
**''Molluscum bodies'' are only the epidermis - an uncommon place to find SRCs without finding them elsewhere.
*The granular eosinophilic cytoplasm represents accumulated virons.


==Superficial dermal infiltrates==
==Superficial dermal infiltrates==
Discussed in detail by Alsaad and Ghazarian.<ref name=pmid16311340>{{Cite journal  | last1 = Alsaad | first1 = KO. | last2 = Ghazarian | first2 = D. | title = My approach to superficial inflammatory dermatoses. | journal = J Clin Pathol | volume = 58 | issue = 12 | pages = 1233-41 | month = Dec | year = 2005 | doi = 10.1136/jcp.2005.027151 | PMID = 16311340 }}</ref>
Discussed in detail by Alsaad and Ghazarian.<ref name=pmid16311340>{{Cite journal  | last1 = Alsaad | first1 = KO. | last2 = Ghazarian | first2 = D. | title = My approach to superficial inflammatory dermatoses. | journal = J Clin Pathol | volume = 58 | issue = 12 | pages = 1233-41 | month = Dec | year = 2005 | doi = 10.1136/jcp.2005.027151 | PMID = 16311340 }}</ref>


===Dermal perivascular lymphoeosinophilic infiltration (DPLI)===
===Dermal perivascular lymphoeosinophilic infiltration===  
*Microscopic appearance is just what it is called:
*Abbreviated ''DPLI''.
**Lymphocytes and eosinophils around the vessels in the superficial dermis.
 
Microscopic appearance is just what it is called:
*Lymphocytes and eosinophils around the vessels in the superficial dermis.


DDx:<ref name=pmid16311340/>
DDx:<ref name=pmid16311340/>
*Insect bite - classically wedge-shaped.<ref name=Ref_PBoD1269>{{Ref PBoD|1269}}</ref>
*Insect bite - classically wedge-shaped.<ref name=Ref_PBoD1269>{{Ref PBoD|1269}}</ref>
*Drug reactions.
*[[Drug reaction]].
*Urticarial reactions.
*Urticarial reaction.
*Prevesicular early stage of [[bullous pemphigoid]].
*Prevesicular early stage of [[bullous pemphigoid]].
*[[HIV]] related dermatoses.
*[[HIV]] related dermatoses.
Line 455: Line 397:


==Mastocytosis==
==Mastocytosis==
===General===
{{Main|Mastocytosis}}
*Abundance of [[mast cell]]s.
 
Classification:<ref name=pmid21083038>{{Cite journal  | last1 = Arock | first1 = M. | last2 = Valent | first2 = P. | title = Pathogenesis, classification and treatment of mastocytosis: state of the art in 2010 and future perspectives. | journal = Expert Rev Hematol | volume = 3 | issue = 4 | pages = 497-516 | month = Aug | year = 2010 | doi = 10.1586/ehm.10.42 | PMID = 21083038 }}</ref>
#Cutaneous (only) - usually children.
#*Urticaria pigmentosa.
#*Others.
#Systemic - usually adults.
#*Indolent subvariant.
#*Aggressive subvariant.
#*Leukemic subvariant.
 
===Microscopic===
Features:<ref name=Ref_PBoD8|1185>{{Ref PBoD8|1185}}</ref>
*Cells in the superficial/mid dermis that are:
**Lymphocyte-like with more cytoplasm that is granular.
***Cells may have spindled or stellate morphology.
***Tend to be more abundant around vessels.
*+/-Eosinophils (common).
*+/-Edema - often prominent; gives cells a white halo.
 
Notes:
*Lymphocyte vs. mast cell:
**Lymphocytes = round; mast cells = ovoid.
 
Images:
*[http://www.jameswpattersonmd.com/case_studies/index.cfm?CFID=387434 Mastocytosis - low res. (jameswpattersonmd.com)].
 
===Stains===
*[[Toluidine blue stain|Toluidine blue]] -- highlights the granules.
 
===IHC===
*CD117 +ve.
*Tryptase +ve.<ref name=pmid21866466>{{Cite journal  | last1 = Rudzki | first1 = Z. | last2 = Sotlar | first2 = K. | last3 = Kudela | first3 = A. | last4 = Starzak-Gwóźdź | first4 = J. | last5 = Horny | first5 = HP. | title = Systemic mastocytosis (SM) and associated malignant bone marrow histiocytosis - a hitherto undescribed form of SM-AHNMD. | journal = Pol J Pathol | volume = 62 | issue = 2 | pages = 101-4 | month =  | year = 2011 | doi =  | PMID = 21866466 }}
</ref>


==Ichthyosis==
==Ichthyosis==
Line 496: Line 404:
*Usu. inherited... thus a pediatric condition.
*Usu. inherited... thus a pediatric condition.


Clinical:
===Gross===
*Fish scale-like appearance.
*Fish scale-like appearance.
Image:
*[http://commons.wikimedia.org/wiki/File:Ichthyosis_1.jpg Ichtyosis (WC)].


===Microscopic===
===Microscopic===
Line 504: Line 415:


==Palmar fibromatosis==
==Palmar fibromatosis==
===General===
*[[AKA]] ''Dupuytren's contracture''.
*[[AKA]] Dupuytren's contracture.
*[[AKA]] ''Dupuytren disease''.
 
{{Main|Palmar fibromatosis}}
Clinical:<ref>URL: [http://www.humpath.com/palmar-fibromatosis http://www.humpath.com/palmar-fibromatosis]. Accessed on: 6 January 2011.</ref>
*Usually older 60-70s.
*Male > female.
*Associated with:
**Alcohol abuse.
*May be familial.
 
===Microscopic===
Features:<ref>URL: [http://surgpathcriteria.stanford.edu/softfib/plantar_fibromatosis/printable.html]. Accessed on: 6 January 2011.</ref>
*Bland spindle cells in dense collagen.
**No nuclear atypia.
*Giant cells.
*+/-Mitotic figures.
 
Images:
*[http://www.biomedsearch.com/attachments/display/00/16/69/68/16696857/1479-5876-4-21-2.jpg Palmer fibromatosis (biomedsearch.com)].<ref name=pmid16696857>{{cite journal |author=Wang L, Zhu H |title=Clonal analysis of palmar fibromatosis: a study whether palmar fibromatosis is a real tumor |journal=J Transl Med |volume=4 |issue= |pages=21 |year=2006 |pmid=16696857 |pmc=1488873 |doi=10.1186/1479-5876-4-21 |url=http://www.biomedsearch.com/nih/Clonal-analysis-palmar-fibromatosis-study/16696857.html}}</ref>


==Angiomyoma==
==Angiomyoma==
Line 541: Line 436:


==Angiokeratoma==
==Angiokeratoma==
===General===
{{Main|Angiokeratoma}}
*Rare.
*May be seen in the context of [[Fabry disease]].<ref name=pmid16403380/>
 
Notes:
*Shouldn't be confused with ''[[angiofibroma]]'' which is associated [[tuberous sclerosis]].
 
===Microscopic===
Features:<ref name=pmid16403380>{{Cite journal  | last1 = Karen | first1 = JK. | last2 = Hale | first2 = EK. | last3 = Ma | first3 = L. | title = Angiokeratoma corporis diffusum (Fabry disease). | journal = Dermatol Online J | volume = 11 | issue = 4 | pages = 8 | month =  | year = 2005 | doi =  | PMID = 16403380 }}</ref>
*Ectatic superficial dermal vessels.
*Overlying hyperkeratosis
 
Others: (???)
*Irregular acanthosis.
*Longer rete ridges.
 
Images:
*[[WC]]:
**[http://commons.wikimedia.org/wiki/File:Angiokeratoma_-_low_mag.jpg Angiokeratoma - low mag. (WC)].
**[http://commons.wikimedia.org/wiki/File:Angiokeratoma_-_intermed_mag.jpg Angiokeratoma - intermed. mag. (WC)].
*www:
**[http://www.pathologyoutlines.com/images/skintumorangiokerat1.jpg Angiokeratoma (pathologyoutlines.com)].
 
DDx:
*[[Venous lake]].


==Inverted follicular keratosis==
==Inverted follicular keratosis==
*Abbreviated ''IFK''.<ref name=pmid11411260>{{Cite journal  | last1 = Shih | first1 = CC. | last2 = Yu | first2 = HS. | last3 = Tung | first3 = YC. | last4 = Tsai | first4 = KB. | last5 = Cheng | first5 = ST. | title = Inverted follicular keratosis. | journal = Kaohsiung J Med Sci | volume = 17 | issue = 1 | pages = 50-4 | month = Jan | year = 2001 | doi =  | PMID = 11411260 }}</ref>
===General===
===General===
*Benign skin lesion.
*Benign skin lesion.
*Central face - middle age.<ref name=Ref_Derm387>{{Ref Derm|387}}</ref>
*Central face - middle age.<ref name=Ref_Derm387>{{Ref Derm|387}}</ref>
*Uncommon.
*Uncommon.
*May be considered a variant of ''[[seborrheic keratosis]]'' that is predominantly endophytic.<ref name=Ref_Derm341>{{Ref Derm|341}}</ref>


Clinical DDx:<ref name=Ref_Derm387>{{Ref Derm|387}}</ref><ref>URL: [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/]. Accessed on: 11 May 2010.</ref>
Clinical DDx:<ref name=Ref_Derm387>{{Ref Derm|387}}</ref><ref>URL: [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/]. Accessed on: 11 May 2010.</ref>
Line 584: Line 457:


DDx:
DDx:
*[[Squamous cell carcinoma]].
*[[Squamous cell carcinoma of the skin]].
*[[Trichilemmoma]].
*[[Trichilemmoma]].
*[[Seborrheic keratosis]] - has an exophytic component.


Images:
Images:
*[http://www.flickr.com/photos/euthman/3059309003/ Inverted follicular keratosis - low mag. (flickr.com)].
*[http://www.flickr.com/photos/euthman/3059309003/ Inverted follicular keratosis - low mag. (flickr.com)].
*[http://www.flickr.com/photos/euthman/3060145702/ Inverted follicular keratosis - high mag. (flickr.com)].
*[http://www.flickr.com/photos/euthman/3060145702/ Inverted follicular keratosis - high mag. (flickr.com)].
*[http://mckeedermpath.com/SPOT%20DIAGNOSIS%20CASE%20474.html Inverted follicular keratosis - several images (mckeedermpath.com)].
===Sign out===
<pre>
SKIN LESION, FACE, BIOPSY:
- INVERTED FOLLICULAR KERATOSIS.
</pre>
====Micro====
The sections show skin with acanthosis, pseudohorn cysts, and focal basal epidermal pigmentation.  There is no basal nuclear atypia, no mitoses and there are no melanocytic nests.  There is minimal dermal inflammation.  There is no apparent solar elastosis.
==Focal cutaneous mucinosis==
===General===
*Benign.
*May be associated with systemic disease.<ref>{{Cite journal  | last1 = Gandhi | first1 = V. | last2 = Dogra | first2 = D. | last3 = Pandhi | first3 = RK. | title = Cutaneous focal mucinosis. | journal = Indian J Dermatol Venereol Leprol | volume = 62 | issue = 4 | pages = 260-1 | month =  | year =  | doi =  | PMID = 20948074 }}</ref>
===Microscopic===
Features:
*Light blue whispy material in the dermis - '''key feature'''.
DDx:
*Dermal edema.
*[[Digital mucous cyst]].


==Panniculitis==
==Panniculitis==
Line 603: Line 500:


=Rare=
=Rare=
==Necrotizing fasciitis==
:'''''Not''' to be confused with [[nodular fasciitis]]''.
*[[AKA]] ''flesh-eating disease''.
{{Main|Necrotizing fasciitis}}
==Porokeratosis==
==Porokeratosis==
===General===
{{Main|Porokeratosis}}
*Genetic.
*Several subtypes.
 
Notes:
*Not the same as ''punctate porokeratotic keratoderma''.<ref name=pmid20137755>{{Cite journal  | last1 = Alikhan | first1 = A. | last2 = Burns | first2 = T. | last3 = Zargari | first3 = O. | title = Punctate porokeratotic keratoderma. | journal = Dermatol Online J | volume = 16 | issue = 1 | pages = 13 | month =  | year = 2010 | doi =  | PMID = 20137755 | URL = http://dermatology.cdlib.org/1601/case_presentations/ppk/alikhan.html }}</ref>
 
===Microscopic===
Features:
*Cornoid lamella (pathognomonic) - '''key feature''':
**Compact keratosis over a hair follicle.
*+/-Rete ridge loss.


==Nevus sebaceous==
==Nevus sebaceous==
*[[AKA]] ''nevus sebaceous of Jadassohn''.
*[[AKA]] ''nevus sebaceous of Jadassohn''.
===General===
{{Main|Nevus sebaceous}}
*Congenital.
*Face or scalp.


===Microscopic===
==Nevus lipomatosus superficialis==
Features:
*Abbreviated ''NLS''.
*Abundant sebaceous glands.
*[[AKA]] ''nevus lipomatosus cutaneous superficialis'', abbreviated ''NLCS''.
*[[AKA]] ''nevus lipomatosus''.<ref name=pmid15677959>{{Cite journal  | last1 = Kaw | first1 = P. | last2 = Carlson | first2 = A. | last3 = Meyer | first3 = DR. | title = Nevus lipomatosus (pedunculated lipofibroma) of the eyelid. | journal = Ophthal Plast Reconstr Surg | volume = 21 | issue = 1 | pages = 74-6 | month = Jan | year = 2005 | doi =  | PMID = 15677959 }}</ref>
{{Main|Nevus lipomatosus superficialis}}


=Bullous disease=
=Bullous disease=

Latest revision as of 17:59, 23 April 2024

Non-malignant skin disease is relatively common. The pathology may or may not be specific. Some diseases require clinical information to diagnose.

An introduction to dermatopathology is in the dermatopathology article. Nevi (moles) and other melanocytic lesions are dealt with in the article melanocytic lesions. Inflammatory skin conditions are dealt with in inflammatory skin disorders.

Other

Lichen simplex chronicus

Main article: Lichen simplex chronicus

Prurigo nodularis

  • Abbreviated PN.
  • AKA chronic prurigo and picker nodule.[1]

General

Gross

  • Dome-shaped/raised - papular (<1 cm) or nodular (>1 cm).[2]

Microscopic

DDx:

Sign out

SKIN LESION, LEFT CHIN, BIOPSY: 
- PRURIGO NODULARIS.

Micro

The sections show a raised lesion with compact hyperkeratosis and irregular acanthosis. Spongiosis is seen focally. There is minimal hypergranulosis.

There is no thinning of the suprapapillary plate and no dilated superficial blood vessels. There is no interface activity.

Very common

Dermatomycosis

Dermatophytosis redirects here.

General

Note:

  • Dermatophytosis (ring worm) is a type of dermatomycosis.

Microscopic

Features:

  • Microorganisms - key feature.
    • Often hyphae (candida) - like twigs of a tree... branching.
      • May be very fragmented in section ~ size of a neutrophil.
  • Perivascular inflammation, esp. neutrophils.
  • Exocytosis - blood cell infiltrate the epidermis.

Images

  • Dermatomycosis - intermed. mag. (WC)

  • Dermatomycosis - high mag. (WC)

  • Dermatomycosis - GMS stain - low mag. (WC)

  • Dermatomycosis - GMS stain - high mag. (WC)

www:

Stains

Sign out

SKIN, BIOPSY:
- SKIN WITH SUPERFICIAL FUNGAL ORGANISMS CONSISTENT WITH CANDIDA.
- REACTIVE CHANGES OF THE EPITHELIUM.

Micro

The sections show skin with a neutrophilic infiltrate in the superficial epidermis. PAS-D staining demonstrates fungal organisms with a morphology suggestive of candida.

The epithelium has parakeratosis, acanthosis and spongiosis. No mitotic activity is appreciated. The keratinocytes are moderately enlarged and have evident nucleoli.

Cicatrix

Main article: Dermal scar

Fibroepithelial polyp

Main article: Fibroepithelial polyp

Actinic keratosis

Main article: Actinic keratosis

Actinic cheilitis

General

Microscopic

See actinic keratosis.

Sign out

LESION, LOWER LIP, BIOPSY: 
- ACTINIC CHEILITIS.
- SOLAR ELASTOSIS.

Micro

The sections show skin with moderate basal nuclear hyperchromasia and atypia, and parakeratosis. The squamous epithelium has maturation to the surface. There is no inflammation at the dermal-epidermal interface. Solar elastosis is present.

Seborrheic keratosis

Main article: Seborrheic keratosis

Pilomatricoma

Main article: Pilomatricoma

Dermatofibroma

Main article: Dermatofibroma

Ezcema

General

  • A nebulous thingy.
  • Very common.

DDx:

Microscopic

Features:[5]

  • Spongiosis (epidermal edema); keratinocytes spacing increased - key feature.
  • +/-Interdermal vesicles.
  • +/-Eosinophils (may suggest Rx reaction).
  • Perivascular lymphocytes.

Acne vulgaris

General

  • Extremely common - esp. among adolescents.
  • Very rarely seen by pathologists.

Treatments:

  • Antibiotic (minocycline).
  • Isotretinoin AKA all-trans retinoic acid (ATRA).

Gross

  • Papules, pustules, nodules or cysts.
    • White, black or erythematous.

Images:

Microscopic

Features:[6]

  • Folliculitis:[7]
    • Neutrophils around hair follicle and infiltrate into it - including the follicular canal.
  • Epidermal invagination or cyst at site of a hair follicle - contains:
    • Sebum.
    • +/-Bacteria (Propionibacterium acnes) and inflammatory cells - typically neurophils.

Subtyped into:

  1. Open comedones ("blackheads") - no extension to epidermal surface.
  2. Closed comedones ("whiteheads") - to epidermal surface have wide opening.

DDx - acneiform disorder:[7]

  • Rosacea.
  • Infective folliculitis.
  • Perioral dermatitis.
  • Acne vulgaris.

Image:

Solar elastosis

General

  • Very common.
  • Caused by sun exposure - specifically UV light.[9]
    • Severity correlated with cumulative exposure to UV light..[10]
  • Often co-localized with skin cancers - as UV light is risk factor for skin cancers.[10]
  • Benign.

Microscopic

Features:

  • Grey, spaghetti-like material in the superficial dermis.

DDx:

Note:

  • The DDx above is things associated with sun damaged skin.
  • Dermal mucin (as my be seen in lupus erythematosus) is a possible mimic - but it isn't spaghetti-like and the "background" (an interface dermatitis) is different.

Images

  • Solar elastosis - intermed. mag. (WC)

  • Solar elastosis - high mag. (WC)

www:

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SKIN, RIGHT CHEEK, RE-EXCISION:
- DERMAL SCAR.
- EXTENSIVE SOLAR ELASTOSIS.
Prominent blood vessels
SKIN LESION, LEFT CHEEK, BIOPSY:
- SKIN WITH SOLAR ELASTOSIS AND PROMINENT SMALL BLOOD VESSELS.

SUPERIOR SHOULDER, LEFT, PUNCH BIOPSY:
- BENIGN SKIN WITH MODERATE SOLAR ELASTOSIS, PROMINENT SMALL BLOOD VESSELS AND
  SCATTERED PERIVASCULAR LYMPHOCYTES AND PLASMA CELLS.
- NEGATIVE FOR BASAL CELL CARCINOMA.
- NEGATIVE FOR ACTINIC KERATOSIS.

Micro

The sections show hair bearing skin with solar elastosis and numerous small dilated blood vessels. The dermis is mildly fibrotic. Compact keratin is present.

The epidermis matures to the surface. A granular layer is present. There is no basal epidermal atypia. No melanocytic nests are identified. There is no palisading of the basal cells. Rare scattered lymphocytes are in the dermis.

Very common - viral

Verruca vulgaris

Main article: Verruca vulgaris

Verruca plana

General

  • Common.
  • Usu. hands and face.[11]

Microscopic

Features:[11]

  • Orthokeratosis with basketweave pattern.
  • Hypergranulosis.
  • Viral keratohyaline.
  • Koilocytes.
  • Acanthosis - yet flat surface and base.

Notes:

  • It differs from verruca vulgaris... (1) orthokeratosis, (2) flat surface and base.

Less common

Chronic folliculitis

Folliculitis redirect here.

General

  • Common.
  • Infrequently biopsied.

Gross

DDx gross:

Microscopic

Features:

  • Inflammation around the hair follicle - key feature.
    • Lymphocytes - usu. predominant.
  • +/-Chronic changes:

DDx:

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SKIN LESION, UPPER ARM, BIOPSY:
- CHRONIC FOLLICULITIS WITH SECONDARY SURFACE CHANGES.

Micro

The sections show hair-bearing skin with abundant lymphocytes around and within the hair follicle wall.

The non-hair follicle epidermis has acanthosis, hypergranulosis and compact hyperkeratosis. There is no inflammatory cell infiltrate in the non-hair follicle epidermis or at the non-hair follicle interface.

There are no granulomas.

Clear cell acanthoma

Main article: Clear cell acanthoma

Chondrodermatitis nodularis chronica helicis

  • AKA chondrodermatitis nodularis helicis.
  • Abbreviated CNCH.
  • AKA Winkler disease.[13]
Main article: Chondrodermatitis nodularis chronica helicis

Cutaneous calcinosis

  • AKA calcinosis cutis.
Main article: Cutaneous calcinosis

Dilated pore of Winer

General

  • Benign.
  • Looks like a zit.

Microscopic

Features:[14]

  • Dilated hair follicle with keratin.
  • Acanthosis.
  • Budding of epidermis (into dermis).

DDx:

Image:

Lichenoid keratosis

  • AKA lichen planus-like keratosis.
Main article: Lichenoid keratosis

Granuloma annulare

Main article: Granuloma annulare

Necrobiosis lipoidica

Main article: Necrobiosis lipoidica

Keloid

Main article: Keloid

Angiofibroma

See also: nasopharyngeal angiofibroma.
Should not be confused with angiokeratoma.
Main article: Angiofibroma

Benign fibrous papule

  • AKA fibrous papule.

General

Gross

  • Solitary lesion of the face - important.[15]
    • Usually on the nose.[16]

Microscopic

Features:[17]

  • Dome-shaped.
  • Fibrotic dermis.
    • Enlarged fibroblasts.
  • Dilated small vessels.
  • +/-Multinucleated stromal cells.[18]
  • +/-Stellate cells.[18]

DDx:

Note:

  • Several variants exist.[16]

Images

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SKIN LESION, CHIN, BIOPSY:
- BENIGN FIBROUS PAPULE.

Molluscum contagiosum

Main article: Molluscum contagiosum

Superficial dermal infiltrates

Discussed in detail by Alsaad and Ghazarian.[19]

Dermal perivascular lymphoeosinophilic infiltration

  • Abbreviated DPLI.

Microscopic appearance is just what it is called:

  • Lymphocytes and eosinophils around the vessels in the superficial dermis.

DDx:[19]

Notes:

  • May superficially resemble cutaneous lymphoma.[20]

Images:

Congenital dermal melanocytosis

  • AKA Mongolian spots.
  • Classically seen in asian children.

Gross:

  • Brown or blue-grey patch in the lumbosacral area.

Mastocytosis

Main article: Mastocytosis

Ichthyosis

General

  • Comes in different flavours.
  • Usu. inherited... thus a pediatric condition.

Gross

  • Fish scale-like appearance.

Image:

Microscopic

Features:[21]

  • Thick stratum corneum without basket-weave pattern.

Palmar fibromatosis

  • AKA Dupuytren's contracture.
  • AKA Dupuytren disease.
Main article: Palmar fibromatosis

Angiomyoma

General

  • Benign.
  • Female > male.[22]

Microscopic

Features:

  • Well-circumscribed lesion with fascicular architecture.
  • Spindle cells/epithelioid cell with moderate eosinophilic (pink) cytoplasm.
  • Thick-walled blood vessels. (???)

Images:

Angiokeratoma

Main article: Angiokeratoma

Inverted follicular keratosis

  • Abbreviated IFK.[23]

General

  • Benign skin lesion.
  • Central face - middle age.[24]
  • Uncommon.
  • May be considered a variant of seborrheic keratosis that is predominantly endophytic.[25]

Clinical DDx:[24][26]

Microscopic

Features:[24]

  • Keratinocyte of cytologically benign proliferation.
  • "Squamous eddies" (whorls of keratin).
  • Coarse keratohyaline granules.

DDx:

Images:

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SKIN LESION, FACE, BIOPSY:
- INVERTED FOLLICULAR KERATOSIS.

Micro

The sections show skin with acanthosis, pseudohorn cysts, and focal basal epidermal pigmentation. There is no basal nuclear atypia, no mitoses and there are no melanocytic nests. There is minimal dermal inflammation. There is no apparent solar elastosis.

Focal cutaneous mucinosis

General

  • Benign.
  • May be associated with systemic disease.[27]

Microscopic

Features:

  • Light blue whispy material in the dermis - key feature.

DDx:

Panniculitis

Main article: Panniculitis

This is dealt with in the panniculitis article.

DDx for panniculitis:

Rare

Necrotizing fasciitis

Not to be confused with nodular fasciitis.
  • AKA flesh-eating disease.
Main article: Necrotizing fasciitis

Porokeratosis

Main article: Porokeratosis

Nevus sebaceous

  • AKA nevus sebaceous of Jadassohn.
Main article: Nevus sebaceous

Nevus lipomatosus superficialis

  • Abbreviated NLS.
  • AKA nevus lipomatosus cutaneous superficialis, abbreviated NLCS.
  • AKA nevus lipomatosus.[28]
Main article: Nevus lipomatosus superficialis

Bullous disease

Main article: Bullous disease

Cysts

Main article: Dermal cysts

See also

References

  1. ↑ Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 26. ISBN 978-0443066542.
  2. ↑ URL: http://www.pediatrics.wisc.edu/education/derm/text.html. Accessed on: 23 August 2012.
  3. ↑ URL: http://missinglink.ucsf.edu/lm/DermatologyGlossary/tinea.html. Accessed on: 25 February 2013.
  4. ↑ Picascia, DD.; Robinson, JK. (Aug 1987). "Actinic cheilitis: a review of the etiology, differential diagnosis, and treatment.". J Am Acad Dermatol 17 (2 Pt 1): 255-64. PMID 3305604.
  5. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1188. ISBN 978-1416031215.
  6. ↑ Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 76. ISBN 978-0443066542.
  7. ↑ 7.0 7.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 77. ISBN 978-0443066542.
  8. ↑ URL: http://www.dermnetnz.org/dermal-infiltrative/solar-elastosis.html. Accessed on: 27 March 2013.
  9. ↑ Thomas, NE.; Kricker, A.; From, L.; Busam, K.; Millikan, RC.; Ritchey, ME.; Armstrong, BK.; Lee-Taylor, J. et al. (Nov 2010). "Associations of cumulative sun exposure and phenotypic characteristics with histologic solar elastosis.". Cancer Epidemiol Biomarkers Prev 19 (11): 2932-41. doi:10.1158/1055-9965.EPI-10-0686. PMID 20802019.
  10. ↑ 10.0 10.1 Karagas, MR.; Zens, MS.; Nelson, HH.; Mabuchi, K.; Perry, AE.; Stukel, TA.; Mott, LA.; Andrew, AS. et al. (Mar 2007). "Measures of cumulative exposure from a standardized sun exposure history questionnaire: a comparison with histologic assessment of solar skin damage.". Am J Epidemiol 165 (6): 719-26. doi:10.1093/aje/kwk055. PMID 17204514.
  11. ↑ 11.0 11.1 Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 480. ISBN 978-0781765275.
  12. ↑ URL: http://www.webmd.com/skin-problems-and-treatments/tc/folliculitis-topic-overview. Accessed on: 7 November 2012.
  13. ↑ URL: http://www.head-face-med.com/content/4/1/2. Accessed on: 16 January 2014.
  14. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 486. ISBN 978-0781765275.
  15. ↑ 15.0 15.1 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 505. ISBN 978-0443066542.
  16. ↑ 16.0 16.1 16.2 Jacyk, WK.; Rütten, A.; Requena, L. (2008). "Fibrous papule of the face with granular cells.". Dermatology 216 (1): 56-9. doi:10.1159/000109359. PMID 18032900.
  17. ↑ Humphrey, Peter A; Dehner, Louis P; Pfeifer, John D (2008). The Washington Manual of Surgical Pathology (1st ed.). Lippincott Williams & Wilkins. pp. 492. ISBN 978-0781765275.
  18. ↑ 18.0 18.1 Ragaz, A.; Berezowsky, V. (1979). "Fibrous papule of the face. A study of five cases by electron microscopy.". Am J Dermatopathol 1 (4): 353-6. PMID 543528.
  19. ↑ 19.0 19.1 Alsaad, KO.; Ghazarian, D. (Dec 2005). "My approach to superficial inflammatory dermatoses.". J Clin Pathol 58 (12): 1233-41. doi:10.1136/jcp.2005.027151. PMID 16311340.
  20. ↑ 20.0 20.1 Cotran, Ramzi S.; Kumar, Vinay; Fausto, Nelson; Nelso Fausto; Robbins, Stanley L.; Abbas, Abul K. (2005). Robbins and Cotran pathologic basis of disease (7th ed.). St. Louis, Mo: Elsevier Saunders. pp. 1269. ISBN 0-7216-0187-1.
  21. ↑ Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson; Aster, Jon (2009). Robbins and Cotran pathologic basis of disease (8th ed.). Elsevier Saunders. pp. 1185. ISBN 978-1416031215.
  22. ↑ Katenkamp D, Kosmehl H, Langbein L (1988). "[Angiomyoma. A pathologo-anatomic analysis of 229 cases]" (in German). Zentralbl Allg Pathol 134 (4-5): 423–33. PMID 3201831.
  23. ↑ Shih, CC.; Yu, HS.; Tung, YC.; Tsai, KB.; Cheng, ST. (Jan 2001). "Inverted follicular keratosis.". Kaohsiung J Med Sci 17 (1): 50-4. PMID 11411260.
  24. ↑ 24.0 24.1 24.2 Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 387. ISBN 978-0443066542.
  25. ↑ Busam, Klaus J. (2009). Dermatopathology: A Volume in the Foundations in Diagnostic Pathology Series (1st ed.). Saunders. pp. 341. ISBN 978-0443066542.
  26. ↑ URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/. Accessed on: 11 May 2010.
  27. ↑ Gandhi, V.; Dogra, D.; Pandhi, RK.. "Cutaneous focal mucinosis.". Indian J Dermatol Venereol Leprol 62 (4): 260-1. PMID 20948074.
  28. ↑ Kaw, P.; Carlson, A.; Meyer, DR. (Jan 2005). "Nevus lipomatosus (pedunculated lipofibroma) of the eyelid.". Ophthal Plast Reconstr Surg 21 (1): 74-6. PMID 15677959.
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