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.  


==General classification (Inflammatory)==
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]]''.
*Bullous.
*Interface.
*Nodular & diffuse.
*Spongiotic.
*Vasculitis.
*Perivascular.
*Panniculitis.
*Psoriasiform.


'''Tabular comparison of inflammatory skin disease (adapted from ''Brister''<ref name=pmid18418089>{{cite journal |author=Brinster NK |title=Dermatopathology for the surgical pathologist: a pattern based approach to the diagnosis of inflammatory skin disorders (part I) |journal=Adv Anat Pathol |volume=15 |issue=2 |pages=76–96 |year=2008 |month=March |pmid=18418089 |doi=10.1097/PAP.0b013e3181664e8d |url=}}</ref>):'''
=Other=
{| class="wikitable"
==Lichen simplex chronicus==
| '''Pattern''' || '''Key histologic feature''' || '''Subclassifications''' || '''Example'''
{{Main|Lichen simplex chronicus}}
|-
| Bullous || "Empty space" || -Subcorneal<br>-Suprabasillar<br>-Subepidermal || -?<br>-?<br>-?
|-
| Interface || Inflammation at DE junction || -Vacuolar (minimal)<br>-Lichenoid (band-like) || -Erythema multiforme<br>-Lichen simplex chronicus (LSC)
|-
| Nodular & diffuse || Nodular & diffuse || ? ||
|-
| Spongiotic || Edema between keratinocytes || -Acute<br>-Subacute<br>-Chronic || -Poison Ivy<br>-Nummular dermatitis<br>-Atopic dermatitis
|-
| Vasculitis || Inflammation of vessel wall || ? || ?
|-
| Perivascular || Inflammation around vessels || ? || ?
|-
| Panniculitis || Inflamm. of SC tissue || -Septal<br>-Nodular ||
|-
| Psoriasiform || Epidermal thickening<br>and long rete ridges || -Regular<br>-Irregular ||
|}
Notes:
*''DE junction'' = dermal-epidermal junction.
*The "empty space" in bullous disease ''in situ'' is filled with fluid.


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


===Microscopy===
===Gross===
*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===
*See ''[[lichen simplex chronicus]]''.
 
DDx:
*[[Lichen simplex chronicus]] - a more diffuse process, not a raised lesion.
 
===Sign out===
<pre>
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=
==Dermatomycosis==
:''Dermatophytosis'' redirects here.
===General===
*[[microorganisms|Fungal infection]] of skin.
 
Note:
*''Dermatophytosis'' (ring worm) is a type of dermatomycosis.
 
===Microscopic===
Features:
Features:
*Loss of rete ridges.
*Microorganisms - '''key feature'''.
*Loss of basal cells (stratum basale).
**Often hyphae (candida) - like twigs of a tree... branching.
*Interface dermatitis (lymphocytes at dermal-epidermal junction).
***May be very fragmented in section ~ size of a neutrophil.
*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>


Ref.: [http://emedicine.medscape.com/article/1078327-overview http://emedicine.medscape.com/article/1078327-overview].
===Stains===
*[[GMS stain]].
*[[PAS-D stain]].


==Lichen sclerosus==  
===Sign out===
*AKA ''chronic atrophic vulvitis'' (when vulvar lesion).
<pre>
SKIN, BIOPSY:
- SKIN WITH SUPERFICIAL FUNGAL ORGANISMS CONSISTENT WITH CANDIDA.
- REACTIVE CHANGES OF THE EPITHELIUM.
</pre>


===Etiology===
====Micro====
*Scratching due to pruritis.
The sections show skin with a neutrophilic infiltrate in the superficial epidermis.  PAS-D staining demonstrates fungal organisms with a morphology suggestive of candida.


===Histology===
The epithelium has parakeratosis, acanthosis and spongiosis. No mitotic activity is appreciated.  The keratinocytes are moderately enlarged and have evident nucleoli.
Key feature:<ref>PBoD P.1065-6</ref>
*Subepithelial fibrosis.


==Lichen simplex chronicus==
==Cicatrix==
===Histology===
{{Main|Dermal scar}}
Key features:<ref>PBoD P.1065-6</ref>
 
*Acanthosis (epithelial thickening).  
==Fibroepithelial polyp==
*Hyperkeratosis.
{{Main|Fibroepithelial polyp}}
 
==Actinic keratosis==
{{Main|Actinic keratosis}}
 
==Actinic cheilitis==
===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===
:See ''[[actinic keratosis]]''.
 
===Sign out===
<pre>
LESION, LOWER LIP, BIOPSY:
- ACTINIC CHEILITIS.
- SOLAR ELASTOSIS.
</pre>
 
====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==
==Seborrheic keratosis==
{{Main|Seborrheic keratosis}}
==Pilomatricoma==
{{Main|Pilomatricoma}}
==Dermatofibroma==
{{Main|Dermatofibroma}}
==Ezcema==
===General===
*A nebulous thingy.
*Very common.
DDx:
*Contact allergy.
*[[Drug reaction]].
*Food allergy.
===Microscopic===
Features:<ref>{{Ref PBoD8|1188}}</ref>
*Spongiosis (epidermal edema); keratinocytes spacing increased - '''key feature'''.
*+/-Interdermal vesicles.
*+/-Eosinophils (may suggest Rx reaction).
*Perivascular lymphocytes.
==Acne vulgaris==
===General===
===General===
*Benign.
*Extremely common - esp. among adolescents.
*Common.
*Very rarely seen by pathologists.


===Epidemiology===
Treatments:
*Old people.
*Antibiotic (minocycline).
*Isotretinoin [[AKA]] all-trans retinoic acid (ATRA).


===Gross===
===Gross===
*"Stuck-on" appearance - raised lesion.
*Papules, pustules, nodules or cysts.
**White, black or erythematous.


Image(s):  
Images:
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=91774460 SK - gross image (dermatlas.org)].
*[http://commons.wikimedia.org/wiki/File:Blackheads.JPG Blackheads (WC)].


===Microscopic===
===Microscopic===
Features:
Features:<ref>{{Ref Derm|76}}</ref>
*Normal appearing epidermis - raised above skin surface.
*Folliculitis:<ref name=Ref_Derm77>{{Ref Derm|77}}</ref>
*"Horn cysts" - collections of keratin.
**[[Neutrophil]]s 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:
#Open comedones ("blackheads") - no extension to epidermal surface.
#Closed comedones ("whiteheads") - to epidermal surface have wide opening.
 
DDx - acneiform disorder:<ref name=Ref_Derm77>{{Ref Derm|77}}</ref>
*[[Rosacea]].
*Infective folliculitis.
*Perioral dermatitis.
*Acne vulgaris.


Image(s):
Image:
*[http://commons.wikimedia.org/wiki/File:Seborrheic_keratosis_(1).jpg Seborrheic keratosis (WC)].
*[http://www.dermnet.com/images/Acne-Histology/picture/4069 Acne (dermnet.com)].
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=-1985374774 Seborrheic keratosis - high mag. (dermatlas.org)].
*[http://www.dermatlas.org/derm/IndexDisplay.cfm?ImageID=-1880960893 Seborrheic keratosis - low mag.  (dermatlas.org)].


==Molluscum contagiosum==
==Solar elastosis==
*Etiology: caused by ''molluscum contagiosum virus''.
*[[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===
*Very common.
*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>
**Severity correlated with cumulative exposure to UV light..<ref name=pmid17204514/>
*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:
Features:
*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>
*Grey, spaghetti-like material in the superficial dermis.
*Molluscum bodies:
 
**Large cells with abundant granular eosinophilic cytoplasm.
DDx:
**Small peripheral nucleus.
*[[Actinic keratosis]].
*[[Basal cell carcinoma]].
*[[Squamous cell carcinoma of the skin|Squamous cell carcinoma]].
 
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====
<gallery>
Image:Solar_elastosis_-_intermed_mag.jpg | Solar elastosis - intermed. mag. (WC)
Image:Solar_elastosis_-_high_mag.jpg | Solar elastosis - high mag. (WC)
</gallery>
www:
*[http://dermpathexpert.com/id88.html Solar elastosis - several images (dermpathexpert.com)].
 
===Sign out===
<pre>
SKIN, RIGHT CHEEK, RE-EXCISION:
- DERMAL SCAR.
- EXTENSIVE SOLAR ELASTOSIS.
</pre>


Image(s):
=====Prominent blood vessels=====
*[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, LEFT CHEEK, BIOPSY:
- SKIN WITH SOLAR ELASTOSIS AND PROMINENT SMALL BLOOD VESSELS.
</pre>


Note:  
<pre>
*Molluscum bodies vaguely resemble ''[[signet ring cell]]s'' -- but:
SUPERIOR SHOULDER, LEFT, PUNCH BIOPSY:
**Cytoplasm eosinophilic and granular.
- BENIGN SKIN WITH MODERATE SOLAR ELASTOSIS, PROMINENT SMALL BLOOD VESSELS AND
**Nucleus usually smaller than in signet ring cell.
  SCATTERED PERIVASCULAR LYMPHOCYTES AND PLASMA CELLS.
**''Molluscum bodies'' are only the epidermis - an uncommon place to find SRCs without finding them elsewhere.
- NEGATIVE FOR BASAL CELL CARCINOMA.
*The granular eosinophilic cytoplasm represents accumulated virons.
- NEGATIVE FOR ACTINIC KERATOSIS.
</pre>


==Dermal nevus==
====Micro====
*Think ''melanoma''.
The sections show hair bearing skin with solar elastosis and numerous small dilated blood vessels.  The dermis is mildly fibrotic. Compact keratin is present.


Clinical: ''ABCD'' = asymmetric, borders (irregular), colour (black), diameter (large).
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|Verruca vulgaris}}
 
==Verruca plana==
===General===
*Common.
*Usu. hands and face.<ref name=Ref_WMSP480>{{Ref WMSP|480}}</ref>


===Microscopic===
===Microscopic===
Features:<ref>need ref</ref>
Features:<ref name=Ref_WMSP480>{{Ref WMSP|480}}</ref>
*Symmetrical lesion.
*Orthokeratosis with basketweave pattern.
*"Matures" with depth - less cellular, less atypia.
*Hypergranulosis.
*No destruction of surrounding structures.
*Viral keratohyaline.
*Only in dermis '''key feature'''.
*Koilocytes.
**Otherwise it is something else, e.g. ''dermal nevus'', ''junctional nevus''.
*[[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===
*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>
 
DDx gross:
*[[Melanocytic lesion]]s.


===Microscopic===
===Microscopic===
*Basaloid cells mixed with squamous cells.  
Features:
*Keratin-filled invaginations.  
*Inflammation around the hair follicle - '''key feature'''.
*Horn cysts - intraepidermal, brown globule-like structures.  
**Lymphocytes - usu. predominant.
**Melanocytes at the dermoepidermal junction.<ref>[http://emedicine.medscape.com/article/1059477-overview http://emedicine.medscape.com/article/1059477-overview]</ref>
*+/-Chronic changes:
**[[Acanthosis]].
**Hyperkeratosis.
**Hypergranulosis.
 
DDx:
*[[Acne vulgaris]].
 
===Sign out===
<pre>
SKIN LESION, UPPER ARM, BIOPSY:
- CHRONIC FOLLICULITIS WITH SECONDARY SURFACE CHANGES.
</pre>
 
====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.


==Pilomatrixoma==
There are no granulomas.
 
==Clear cell acanthoma==
{{Main|Clear cell acanthoma}}
 
==Chondrodermatitis nodularis chronica helicis==
*[[AKA]] ''chondrodermatitis nodularis helicis''.
*Abbreviated ''CNCH''.
*[[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>
{{Main|Chondrodermatitis nodularis chronica helicis}}
 
==Cutaneous calcinosis==
*[[AKA]] ''calcinosis cutis''.
{{Main|Cutaneous calcinosis}}
 
==Dilated pore of Winer==
===General===
===General===
*Benign skin tumour.
*Benign.
*Most common solid skin tumour of children.<ref name=emed1058965>[http://emedicine.medscape.com/article/1058965-overview http://emedicine.medscape.com/article/1058965-overview]</ref>
*Looks like a zit.


Clinical:
===Microscopic===
*Hard nodule - calcification.
Features:<ref name=Ref_WMSP486>{{Ref WMSP|486}}</ref>
*+/-Painful. (???)
*Dilated hair follicle with keratin.
*[[Acanthosis]].
*Budding of epidermis (into dermis).


Treatment:
DDx:
*Surgical excision.<ref name=emed1058965>[http://emedicine.medscape.com/article/1058965-overview http://emedicine.medscape.com/article/1058965-overview]</ref>
*[[Pilar sheath acanthoma]].
 
Image:
*[http://dermpathexpert.com/id90.html Dilated pore of Winer (dermpathexpert.com)].
 
==Lichenoid keratosis==
*[[AKA]] ''lichen planus-like keratosis''.
{{Main|Lichenoid keratosis}}
 
==Granuloma annulare==
{{Main|Granuloma annulare}}
 
==Necrobiosis lipoidica==
{{Main|Necrobiosis lipoidica}}
 
==Keloid==
{{Main|Keloid}}
 
==Angiofibroma==
:See also: ''[[nasopharyngeal angiofibroma]]''.
:Should '''not''' be confused with ''[[angiokeratoma]]''.
{{Main|Angiofibroma}}
 
==Benign fibrous papule==
*[[AKA]] ''fibrous papule''.
 
===General===
*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>
 
===Gross===
*Solitary lesion of the face - '''important'''.<ref name=Ref_Derm505>{{Ref Derm|505}}</ref>
**Usually on the nose.<ref name=pmid18032900/>


===Microscopic===
===Microscopic===
Features:<ref name=emed1058965dx>[http://emedicine.medscape.com/article/1058965-diagnosis http://emedicine.medscape.com/article/1058965-diagnosis]</ref>
Features:<ref name=Ref_WMSP492>{{Ref WMSP|492}}</ref>
*Location: lower dermis/subcutaneous fat; thus, usu. surrounded by connective tissue.
*Dome-shaped.
*Sharpy demarcated island of cells.
*Fibrotic dermis.
*Calcification in 75% - with calcium staining (von Kossa).  
**Enlarged fibroblasts.
*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>
*Dilated small vessels.
**Basaloid epithelial cells - have prominent nucleoli.
*+/-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>
**Anucleate squamous cells ("ghost cells").  
*+/-Stellate cells.<ref name=pmid543528/>
*Giant cell foreign body type granulomas (form in reaction to keratin).
 
DDx:
*[[Angiofibroma]] - not solitary or not on the nose.
 
Note:
*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>
 
===Images===
*[http://www.dermaamin.com/site/histopathology-of-the-skin/58-f/1739-fibrous-papule-angiofibroma-.html Fibrous papule (dermaamin.com)].
 
===Sign out===
<pre>
SKIN LESION, CHIN, BIOPSY:
- BENIGN FIBROUS PAPULE.
</pre>
 
==Molluscum contagiosum==
{{Main|Molluscum contagiosum}}
 
==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>
 
===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:<ref name=pmid16311340/>
*Insect bite - classically wedge-shaped.<ref name=Ref_PBoD1269>{{Ref PBoD|1269}}</ref>
*[[Drug reaction]].
*Urticarial reaction.
*Prevesicular early stage of [[bullous pemphigoid]].
*[[HIV]] related dermatoses.


Notes:
Notes:
*Keratin a prominent feature on cytology - lots of orange stuff.
*May superficially resemble cutaneous lymphoma.<ref name=Ref_PBoD1269>{{Ref PBoD|1269}}</ref>


Images:
Images:
*[http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ngcase02.htm Pilomatrixoma - cytology (bccancer.bc.ca)].
*[http://en.wikipedia.org/wiki/File:Dermal_perivascular_lymphoeosinophilic_infiltrate_-_very_low_mag.jpg DPLI - very low mag. (WC)].
*[http://www.dermrounds.com/photo/1980062:Photo:431 Pilomatrixoma - histology (dermrounds.com)].
*[http://en.wikipedia.org/wiki/File:Dermal_perivascular_lymphoeosinophilic_infiltrate_-_very_high_mag.jpg DPLI - very high mag. (WC)].
DDx:
 
*Epidermal inclusion cyst.
==Congenital dermal melanocytosis==
*[[AKA]] ''Mongolian spots''.
*Classically seen in asian children.
 
Gross:
*Brown or blue-grey patch in the lumbosacral area.
 
==Mastocytosis==
{{Main|Mastocytosis}}
 
==Ichthyosis==
===General===
*Comes in different flavours.
*Usu. inherited... thus a pediatric condition.
 
===Gross===
*Fish scale-like appearance.
 
Image:
*[http://commons.wikimedia.org/wiki/File:Ichthyosis_1.jpg Ichtyosis (WC)].
 
===Microscopic===
Features:<ref name=Ref_PBoD8|1185>{{Ref PBoD8|1185}}</ref>
*Thick stratum corneum without basket-weave pattern.
 
==Palmar fibromatosis==
*[[AKA]] ''Dupuytren's contracture''.
*[[AKA]] ''Dupuytren disease''.
{{Main|Palmar fibromatosis}}


==Syringoma==
==Angiomyoma==
*Benign sweat duct tumour. (???)
*Do '''not''' confuse with ''[[aggressive angiomyxoma|angiomyxoma]]''.
*Eccrine differentiation.
===General===
*Benign.
*Female > male.<ref name=pmid3201831 >{{cite journal |author=Katenkamp D, Kosmehl H, Langbein L |title=[Angiomyoma. A pathologo-anatomic analysis of 229 cases] |language=German |journal=Zentralbl Allg Pathol |volume=134 |issue=4-5 |pages=423–33 |year=1988 |pmid=3201831 |doi= |url=}}</ref>


===Microscopic===
===Microscopic===
Features:<ref>URL: [http://emedicine.medscape.com/article/1059871-diagnosis http://emedicine.medscape.com/article/1059871-diagnosis]. Accessed on: 12 May 2010.</ref>
Features:
*Proliferation of benign ducts with lined by a bilayer (as in normal sweat ducts) with abnormal architecture:
*Well-circumscribed lesion with [[fascicular]] architecture.
**Tadpole like appearing ducts.
*Spindle cells/epithelioid cell with moderate eosinophilic (pink) cytoplasm.
*Thick-walled blood vessels. (???)
 
Images:
*[http://commons.wikimedia.org/wiki/File:Cutaneous_angiomyoma_%281%29.jpg Angiomymoma (WC)].
*[http://commons.wikimedia.org/wiki/File:Cutaneous_angiomyoma_%282%29.jpg Angiomymoma (WC)].


Image:
==Angiokeratoma==
*[http://www.flickr.com/photos/euthman/2329061316/ Syringoma (flickr.com)].
{{Main|Angiokeratoma}}


==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===
*Benign skin lesion.
*Benign skin lesion.
*Rare.
*Central face - middle age.<ref name=Ref_Derm387>{{Ref Derm|387}}</ref>
*May mimic squamous cell carcinoma or basal cell carcinoma.<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>
*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>
*[[BCC]].
*[[Wart]].
 
===Microscopic===
Features:<ref name=Ref_Derm387>{{Ref Derm|387}}</ref>
*Keratinocyte of cytologically benign proliferation.
*"Squamous eddies" (whorls of keratin).
*Coarse keratohyaline granules.
 
DDx:
*[[Squamous cell carcinoma of the skin]].
*[[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.


==Dermal cylindroma==
==Focal cutaneous mucinosis==
===General===
===General===
*Benign skin lesion.
*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===
===Microscopic===
Features:
Features:
*Nests of cells that are surrounded by hyaline (i.e. glassy, eosinophilic, acellular) material.  
*Light blue whispy material in the dermis - '''key feature'''.
 
DDx:
*Dermal edema.
*[[Digital mucous cyst]].
 
==Panniculitis==
{{Main|Panniculitis}}
This is dealt with in the ''[[panniculitis]]'' article.


Images:
DDx for panniculitis:
*[http://commons.wikimedia.org/wiki/File:Dermal_cylindroma_intermed_mag.jpg Dermal cylindroma (WC)].
*[[Erythema nodosum]].
*[http://commons.wikimedia.org/wiki/File:Dermal_cylindroma_intermed_mag_deep.jpg Dermal cylindroma - high mag. (WC)].
*[[Erythema induratum]].
*Self-inflicted trauma.
*[[Systemic lupus erythematosus]].
*Weird stuff.


==Keratoacanthoma==
=Rare=
*Abbreviated ''KA''.
==Necrotizing fasciitis==
*Generally considered to be benign.
:'''''Not''' to be confused with [[nodular fasciitis]]''.
**Rare reports of metastases suggesting it may be a form of squamous cell carcinoma.<ref>{{cite journal |author=Mandrell JC, Santa Cruz D |title=Keratoacanthoma: hyperplasia, benign neoplasm, or a type of squamous cell carcinoma? |journal=Semin Diagn Pathol |volume=26 |issue=3 |pages=150–63 |year=2009 |month=August |pmid=20043514 |doi= |url=}}</ref>
*[[AKA]] ''flesh-eating disease''.
{{Main|Necrotizing fasciitis}}


===Clinical===
==Porokeratosis==
*May grow rapidly (weeks or months) then involute.
{{Main|Porokeratosis}}
*Main DDx is squamous cell carcinoma.
*Exophytic lesion, well-circumscribed.


===Microscopic===
==Nevus sebaceous==
Features:<ref>Klatt. AOP. P. 378.</ref>
*[[AKA]] ''nevus sebaceous of Jadassohn''.
*Expansion of stratum spinosum - pushing tongue-like downward growth of epidermis into the dermis.
{{Main|Nevus sebaceous}}
*Keratin collection (keratin plug) at the center of lesion-superficial aspect.
*Cells have glassy pink cytoplasm.
*Minimal/no nuclear atypia.


Image:
==Nevus lipomatosus superficialis==
*[http://commons.wikimedia.org/wiki/File:Skin_keratoacanthoma_whole_slide.jpg Keratocanthoma (WC).]
*Abbreviated ''NLS''.
*[[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=
{{main|Bullous disease}}
{{main|Bullous disease}}


==Cysts==
=Cysts=
{{main|Dermal cysts}}
{{main|Dermal cysts}}


==See also==
=See also=
*[[Dermatopathology introduction]].
*[[Dermatopathology introduction]].
*[[Malignant skin disease]].
*[[Malignant skin disease]].


==References==
=References=
{{reflist|2}}
{{reflist|2}}


[[Category:Non-malignant skin disease]]
[[Category:Non-malignant skin disease]]
[[Category:Dermatopathology]]
[[Category:Dermatopathology]]

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

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

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

Fibroepithelial polyp

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

Pilomatricoma

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

www:

Sign out

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

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:

Sign out

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

Chondrodermatitis nodularis chronica helicis

  • AKA chondrodermatitis nodularis helicis.
  • Abbreviated CNCH.
  • AKA Winkler disease.[13]

Cutaneous calcinosis

  • AKA calcinosis cutis.

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.

Granuloma annulare

Necrobiosis lipoidica

Keloid

Angiofibroma

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

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

Sign out

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

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

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.

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

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:

Sign out

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

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.

Porokeratosis

Nevus sebaceous

  • AKA nevus sebaceous of Jadassohn.

Nevus lipomatosus superficialis

  • Abbreviated NLS.
  • AKA nevus lipomatosus cutaneous superficialis, abbreviated NLCS.
  • AKA nevus lipomatosus.[28]

Bullous disease

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.