Dermatopathology

Question 1

Eczematous Dermatitis

Answer 1

gross: diffuse erythema, edema, oozing and crusting, vesicles, bullae
histo: intraepidermal vesicles between keratinocytes (spongiosis), PMN infiltrate

allergic contact dermatitis— Type 4 delayed hypersensitivty

Question 2

Pemphigus Vulgaris

Answer 2

gross: combination of lesions (oral and corporal) vesicles and bullae that easily rupture
- -odynophagia constituionsl==> wt loss

histo: linear deposits of IgG and C3 seen along basement membrane with immunofluoresence.

epidermis split above basal layer—acantholysis—dissolution of desmosomes holding together epidermis.

pts have circulating anti-desmoglein Ig
–autoimmune

distinct from bullous pemphigoid==> affects the elderly, Ab against Hemidesmosomes.

Question 3

Erythema Multiforme

Answer 3

gross- erythematous papule with central vesicle–characteristic targetoid appearance. some constitutional symptoms may be present.

histo: perivascular PMN infiltrate is present. subepidermal vesicle and bullae formation. dermal edema, subepidermal blisters

Self-contained autoimmune rxn (type 4) to drugs, infection, malignancy

Subtype– Stevens-Johnson Syndrome==> drug rxn, involves mucosa

Question 4

Psoriasis

Answer 4

gross- sharply demarcated salmon colored plaques and papules covered in white scales. scalp, sacral areas, extensor surfaces of extremities

histo: parakeratosis, acanthosis, elongated rete ridges, PMN in parakeratotic layer.

chronic inflammatory dermatosis.

can affect nails

Question 5

Seborrheic Keratosis

Answer 5

Gross- large, brown/red/flesh/black papules/plaques with characteristic “stuck on” appearance

Histo: hyperkeratosis, acanthosis, melanocytic hyperplasia, papillomatosis

—can resemble malignant melanoma

darker lesions show increased melanin.

“straight line” can be seen at the bottom of the epidermis.

Question 6

Dermatofibroma

Answer 6

gross- small, firm, pink to brown dull to shiny lesions with ill defined borders— dimple when laterally compressed

histo: proliferation of dermal fibroblasts, fibroblasts seem to hug collagen bundles. fibroblasts have characteristic spindle shape.

totally benign, will spontaneously regress

Question 7

Basal Cell Carcinoma

Answer 7

gross- head and neck region (sun exposed), pearly papule, can be telangectactic with central ulceration.

histo—-islands or cords of basaloid cells arising from the basal layer of the epidermis. palisading row of basal cell will clearly demarcate the tumor.

• –hyperchromatic nuclei
• – “clefting” due to retraction artifact of stromal cells

NO metastasis, cvan be invasive to bone.

Question 8

Actinic Keratosis

Answer 8

gross- rough scclay patches associated with areas of XS sun exposure. can have hard cutaneous horns.

—premalignant (will lead to squamous cell carcinoma)

histo- hyperkeratosis/parakeratosis.

Question 9

Squamous Cell Carcinoma

Answer 9

gross- raised nodule with erythematous indurated border. Ususally seen with central ulceration. scaling

histo- full thickness epidermal atypia—invasive, pleomorphism, nuclear hyperchromasia, atypical mitotic figures. epidermal “bulldozing” into dermal layer. Keratin pearls can be seen. tumor will appear more pink since it makes keratin.

areas of chronic inflammation can lead to SCC

keratoacanthoma—> well differentiated SCC with characteristic volcano appearence

Question 10

Malignant Melanoma

Answer 10

gross- judged by ABCDE criteria (assymetry, border, color variation, diameter, elevation) lesions are usually > 6mm at time of dx.

histo— large, irregular, hyperchromatic nuclei, cytoplasm will may have variable amount of dusty melanin pigment.

biggest prognostic indicator==> Breslow depth– distance from top of granular layer to deepest invasion (<1.7mm=good)

malignant melanocytes can be seen as nests of poorly staining cells at the dermal/epidermal boundary.