Ch. 25 Key Concepts

Question 1

most melanocytic nevi have activating mutations in which genes?

Answer 1

BRAF, or less often NRAS

- the vast majority never undergo malignant transformation

Question 2

most of these are best regarded as markers of melanoma risk rather than premalignant lesions
- they are characterized by architectural and cytologic atypia and are associated with germline mutation in genes encoding cell cycle regulators (p16/INK4a, CDK4) and telomerase

Answer 2

dysplastic nevi

Question 3

highly aggressive malignancy linked to sun exposure
- risk of spread is predicted by a number of tumor characteristics, particularly the vertical thickness of excised tumors

Answer 3

melanoma
- often incites a host immune response and sometimes shows dramatic responses to antibody therapies that enhance T-cell immunity

Question 4

what mutations are associated with melanoma?

Answer 4

• cell cycle regulators: p16/INK4a, CDK4
• pro-growth signaling factors: KIT, RAS, BRAF
• telomerase

Question 5

the incidence of both basal cell and squamous cell carcinoma is strongly correlated with what?

Answer 5

increasing lifetime sun exposure

Question 6

this type of carcinoma can progress from actinic keratoses but also arises from chemical exposure at thermal burn sites
- or in association with HPV infection in the setting of immunosuppression

Answer 6

cutaneous squamous cell carcinoma

Question 7

this carcinoma has potential for metastasis but is much less aggressive than squamous cell carcinoma at mucosal sites

Answer 7

cutaneous squamous cell carcinoma

Question 8

the most common malignancy worldwide

• is a locally aggressive tumor associated with mutations that activate Hedgehog signaling
• metastasis is very rare

Answer 8

basal cell carcinoma

Question 9

classified based on the level of epidermal separation
- often caused by autoantibodies specific for epithelial or basement membrane proteins that lead to unmooring of keratinocytes

Answer 9

blistering disorders

Question 10

associated with IgG autoantibodies to various intercellular desmogleins
- results in bullae that are either subcorneal or suprabasilar

Answer 10

pemphigus

• subcorneal = pemphigus foliaceus
• suprabasilar = pemphigus vulgaris

Question 11

associated with IgA autoantibodies to fibrils that bind the epidermal basement membrane to the dermis
- also produce subepidermal blisters

Answer 11

dermatitis herpetiformis