24-year-old woman presents with multiple atypical nevi. Almost all lesions had mild atypia, few had focally moderate atypia, and one on her right posterior shoulder had severe atypia and was excised with 5mm margins elsewhere. Family history is significant for melanoma in grandmother and pancreatic cancer in her father. Physical exam showed multiple 2-4 mm benign appearing pigmented macules.
This young patient presents with a dysplastic nevus syndrome in the setting of strong family history of hereditary melanoma. Testing for p16 gene (CDKN2A) is indicated. Mutations of p16 are responsible for 20-40 % of cases of hereditary melanoma. This mutation is also responsible for increased risk of pancreatic cancer. Testing for the p16 mutation should be done in the setting of genetic counseling.