A 64-year-old man has noted changes in the texture and color of skin in his armpit and groin over the past 3 months. On physical examination, there is thickened, darkly pigmented skin in the axillae and flexural areas of the neck and groin. These areas are neither painful nor pruritic. A punch biopsy specimen of axillary skin shows undulating epidermal acanthosis with hyperkeratosis and basal layer hyperpigmentation. Which of the following underlying diseases is most likely to be present in this patient?
□ (A) Systemic lupus erythematosus
□ (B) Mastocytosis
□ (C) AIDS
□ (D) Colonic adenocarcinoma
□ (E) Langerhans cell histiocytosis
