A 64-year-old male noticed the development over the past 3 months of thickened, darkly pigmented skin in axillae and flexural areas of the neck and groin. These areas are neither painful nor pruritic. A punch biopsy of axillary skin reveals undulating epidermal acanthosis with hyperkeratosis and' basal layer hyper pigmentation. Which of the following underlying diseases is he most likely to have?

He has findings typical of acanthosis nigricans, a cutaneous marker for benign and malignant neoplasms. The skin lesions often precede signs and symptoms of associated cancers. They are believed to arise from the action of epidermal growth-promoting factors made by. neoplasms. The rashes that develop with SLE are the result of antigenantibody complex deposition and often exhibit photosensitivity. 'Skin lesions of mastocytosis in adults often exhibit uicaria. There are a variety of skin lesions with AIDS, including disseminated infections and a variety of papulosquamous dermatoses, although not pigmented lesions. "Involvement of the skin with Langerhans cell histiocytoses typically occurs in children and produces reddish papules or nodules or erythematous scaling plaques because of the histiocytic infiltrates in the dermis.