Neoplasia USMLE Step 1 Practice Question
A 58-year-old woman with a history of atypical moles presents to dermatology with a 3-month history of a rapidly enlarging pigmented lesion on her back. She reports fair skin, significant sun exposure during childhood, and a family history of melanoma. On examination, the lesion measures 8 mm in diameter with irregular borders, asymmetry, and color variation ranging from tan to dark brown to black. Dermoscopy reveals a disorganized architecture with increased vascularity. Excisional biopsy demonstrates a melanoma with Breslow thickness of 1.5 mm, increased mitotic rate, and ulceration. Which of the following mutations is the most common initiating genetic alteration in this patient's tumor?
Answer choices
- ATP53 mutation
- BBRAF V600E mutationCorrect answer
- CNRAS Q61 mutation
- DKIT mutation
- EPTEN loss
- FNF1 inactivation
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.