Non-malignant skin disease
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)
- Bullous.
- Interface.
- Nodular & diffuse.
- Spongiotic.
- Vasculitis.
- Perivascular.
- Panniculitis.
- Psoriasiform.
Tabular comparison of inflammatory skin disease (adapted from Brister[1]):
Pattern | Key histologic feature | Subclassifications | Example |
Bullous | "Empty space" | -Subcorneal -Suprabasillar -Subepidermal |
-? -? -? |
Interface | Inflammation at DE junction | -Vacuolar (minimal) -Lichenoid (band-like) |
-Erythema multiforme -Lichen simplex chronicus (LSC) |
Nodular & diffuse | Nodular & diffuse | ? | |
Spongiotic | Edema between keratinocytes | -Acute -Subacute -Chronic |
-Poison Ivy -Nummular dermatitis -Atopic dermatitis |
Vasculitis | Inflammation of vessel wall | ? | ? |
Perivascular | Inflammation around vessels | ? | ? |
Panniculitis | Inflamm. of SC tissue | -Septal -Nodular |
|
Psoriasiform | Epidermal thickening and long rete ridges |
-Regular -Irregular |
Notes:
- DE junction = dermal-epidermal junction.
- The "empty space" in bullous disease in situ is filled with fluid.
Lichen planus
General
Microscopy
Features:
- Loss of rete ridges.
- Loss of basal cells (stratum basale).
- Interface dermatitis (lymphocytes at dermal-epidermal junction).
Ref.: http://emedicine.medscape.com/article/1078327-overview.
Images:
Lichen sclerosus
- AKA chronic atrophic vulvitis (when vulvar lesion).
Etiology
- Scratching due to pruritis.
Histology
Key feature:[4]
- Subepithelial fibrosis.
Lichen simplex chronicus
General
- Variant of spongiotic dermatitis.[5]
Etiology:[6]
- Pruritus -> mechanical trauma -> lichenification (thickened/leathery[7].
Microscopic
Features:[4]
- Acanthosis (epithelial thickening).
- Hyperkeratosis.
Other features:[8]
- Spongiosis (epidermal intercellular edema -- cells appear to have a clear halo around 'em).
- Parakeratosis = retention of nuclei in the stratum corneum.
Images:
Seborrheic keratosis
General
- Benign.
- Common.
Epidemiology
- Old people.
Gross
- "Stuck-on" appearance - raised lesion.
Image(s):
Microscopic
Features:
- Normal appearing epidermis - raised above skin surface.
- "Horn cysts" - collections of keratin.
Image(s):
- Seborrheic keratosis (WC).
- Seborrheic keratosis - high mag. (dermatlas.org).
- Seborrheic keratosis - low mag. (dermatlas.org).
Verruca vulgaris
General
- AKA Wart.
- Etiology: HPV. (???)
Microscopic
Features:
- Hyperkeratosis (more keratin - thick stratum corneum).
- Hypergranulosis (thicker stratum granulosum).
- Rete ridges lengthened (~7-10x normal).
- Acanthosis (thickening of the stratum spinosum).
- Large blood vessels at the dermal-epidermal junction.
Ref.:[9]
Molluscum contagiosum
- Etiology: caused by molluscum contagiosum virus.
Microscopic
Features:
- A suprabasilar epidermal lesion consisting of "molluscum bodies", i.e. molluscum bodies are found above the stratum basale.[10]
- Molluscum bodies:
- Large cells with abundant granular eosinophilic cytoplasm.
- Small peripheral nucleus.
Image(s):
Note:
- Molluscum bodies vaguely resemble signet ring cells -- but:
- 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.
Dermal nevus
- Think melanoma.
Clinical: ABCD = asymmetric, borders (irregular), colour (black), diameter (large).
Microscopic
Features:[11]
- Symmetrical lesion.
- "Matures" with depth - less cellular, less atypia.
- No destruction of surrounding structures.
- Only in dermis key feature.
- Otherwise it is something else, e.g. dermal nevus, junctional nevus.
Microscopic
- Basaloid cells mixed with squamous cells.
- Keratin-filled invaginations.
- Horn cysts - intraepidermal, brown globule-like structures.
- Melanocytes at the dermoepidermal junction.[12]
Pilomatrixoma
General
- Benign skin tumour.
- Most common solid skin tumour of children.[13]
Clinical:
- Hard nodule - calcification.
- +/-Painful. (???)
Treatment:
- Surgical excision.[13]
Microscopic
Features:[14]
- Location: lower dermis/subcutaneous fat; thus, usu. surrounded by connective tissue.
- Sharpy demarcated island of cells.
- Calcification in 75% - with calcium staining (von Kossa).
- Cells:[15]
- Basaloid epithelial cells - have prominent nucleoli.
- Anucleate squamous cells ("ghost cells").
- Giant cell foreign body type granulomas (form in reaction to keratin).
Notes:
- Keratin a prominent feature on cytology - lots of orange stuff.
Images:
DDx:
- Epidermal inclusion cyst.
Syringoma
- Benign sweat duct tumour. (???)
- Eccrine differentiation.
Microscopic
Features:[16]
- Proliferation of benign ducts with lined by a bilayer (as in normal sweat ducts) with abnormal architecture:
- Tadpole like appearing ducts.
Image:
Inverted follicular keratosis
- Benign skin lesion.
- Rare.
- May mimic squamous cell carcinoma or basal cell carcinoma.[17]
Images:
- Inverted follicular keratosis - low mag. (flickr.com).
- Inverted follicular keratosis - high mag. (flickr.com).
Dermal cylindroma
General
- Benign skin lesion.
- Should not be confused with cylindroma (adenoid cystic carcinoma).
Microscopic
Features:
- Nests of cells that are surrounded by hyaline (i.e. glassy, eosinophilic, acellular) material.
Images:
Keratoacanthoma
- Abbreviated KA.
- Generally considered to be benign.
- Rare reports of metastases suggesting it may be a form of squamous cell carcinoma.[18]
Clinical
- May grow rapidly (weeks or months) then involute.
- Main DDx is squamous cell carcinoma.
- Exophytic lesion, well-circumscribed.
Microscopic
Features:[19]
- Expansion of stratum spinosum - pushing tongue-like downward growth of epidermis into the dermis.
- Keratin collection (keratin plug) at the center of lesion-superficial aspect.
- Cells have glassy pink cytoplasm.
- Minimal/no nuclear atypia.
Image:
Dermatofibroma
General
- AKA fibrous histiocytoma.
- Reactive process -- it is not a neoplasm.
- Usually assoc. with previous trauma.
- In women... usually legs.
Microscopic
Features:[20]
- Prominent fibrous bundles, especially at the edge of the lesion.
- Surrounded by spindle cells (fibroblasts).
- Usually thought of as fibroblasts surrounded by fibrous material ("collagen-trapping").
- Surrounded by spindle cells (fibroblasts).
- Lack of adnexal structures, i.e. no sweat glands, no hair.
- +/-Acanthosis (thickened epithelial layer - specifically thickened stratum spinosum) with basal keratinocyte hyperpigmentation.
- May vaguely resemble basal cell carcinoma.
Images:
DDx:
- Neurofibroma.
- Blue nevus.
- Dermatofibroma pertuberans (DFSP).
- Melanoma.
Superficial dermal infiltrates
Discussed in detail by Alsaad and Ghazarian.[21]
Dermal perivascular lymphoeosinophilic infiltration (DPLI)
- Microscopic appearance is just what it is called:
- Lymphocytes and eosinophils around the vessels in the superficial dermis.
DDx:[21]
- Insect bite.
- Drug reactions.
- Urticarial reactions.
- Prevesicular early stage of bullous pemphigoid.
- HIV related dermatoses.
Images:
Bullous disease
Cysts
See also
References
- ↑ Brinster NK (March 2008). "Dermatopathology for the surgical pathologist: a pattern based approach to the diagnosis of inflammatory skin disorders (part I)". Adv Anat Pathol 15 (2): 76–96. doi:10.1097/PAP.0b013e3181664e8d. PMID 18418089.
- ↑ Teichman, JM.; Sea, J.; Thompson, IM.; Elston, DM. (Jan 2010). "Noninfectious penile lesions.". Am Fam Physician 81 (2): 167-74. PMID 20082512.
- ↑ Gupta, R.; Bansal, B.; Singh, S.; Yadav, I.; Gupta, K.; Kudesia, M. (2009). "Lichen planus of uterine cervix - the first report of a novel site of occurrence: a case report.". Cases J 2: 9306. doi:10.1186/1757-1626-2-9306. PMID 20062629.
- ↑ 4.0 4.1 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. 1065-6. ISBN 0-7216-0187-1.
- ↑ Tadrous, Paul.J. Diagnostic Criteria Handbook in Histopathology: A Surgical Pathology Vade Mecum (1st ed.). Wiley. pp. 296. ISBN 978-0470519035.
- ↑ URL: http://emedicine.medscape.com/article/1123423-overview. Accessed on: 20 August 2010.
- ↑ URL: http://www.medterms.com/script/main/art.asp?articlekey=10131. Accessed on: 20 August 2010.
- ↑ URL: http://emedicine.medscape.com/article/1123423-diagnosis. Accessed on: 20 August 2010.
- ↑ URL: http://missinglink.ucsf.edu/lm/DermatologyGlossary/verruca_vulgaris.html. Accessed on: 14 July 2010.
- ↑ http://www.missionforvisionusa.org/anatomy/2006/08/what-is-molluscum-contagiosum.html
- ↑ need ref
- ↑ http://emedicine.medscape.com/article/1059477-overview
- ↑ 13.0 13.1 http://emedicine.medscape.com/article/1058965-overview
- ↑ http://emedicine.medscape.com/article/1058965-diagnosis
- ↑ http://www.bccancer.bc.ca/HPI/CE/cytotechnology/cytosleuthquiz/nongyne/ngcase02d.htm
- ↑ URL: http://emedicine.medscape.com/article/1059871-diagnosis. Accessed on: 12 May 2010.
- ↑ URL: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC475744/. Accessed on: 11 May 2010.
- ↑ Mandrell JC, Santa Cruz D (August 2009). "Keratoacanthoma: hyperplasia, benign neoplasm, or a type of squamous cell carcinoma?". Semin Diagn Pathol 26 (3): 150–63. PMID 20043514.
- ↑ Klatt. AOP. P. 378.
- ↑ 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.
- ↑ 21.0 21.1 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.