A fair-skinned man, age 60 years, presented after his wife noted blood spots on the inside of his undershirt. An asymptomatic lesion was discovered on his right upper back. This lesion was a 6 × 3.5 cm superficial papulosquamous plaque with an annular well-defined border, within which were scattered tiny focal areas of erosion. Dark red focal areas were found within the borders of the lesion. The lesion had been present for at least five years before it began to bleed. At no point had it been painful or itchy, and it had grown quite slowly.
A 27-year-old man was referred to the dermatology clinic for evaluation of an asymptomatic leg lesion. The lesion first appeared two years ago and doubled in size during that period. The patient’s primary-care clinician had diagnosed the lesion as “ringworm” and psoriasis. Various creams, including a combination product containing betamethasone and clotrimazole, had had no effect. Additional history included newly diagnosed diabetes mellitus. No fever, cough, shortness of breath, or unexplained weight loss were reported.
What is the diagnosis?
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