Coexistent urticaria pigmentosa, acromegaly and acanthosis nigricans.

We report a case of urticaria pigmentosa, acromegaly and acanthosis nigricans in a 25-year-old male. The patient exhibited multiple pigmented papules on the trunk and the extremities. Histological examinations of the papules revealed infiltrates of mast cells in the upper dermis. Ultrastructurally, the mast cells were fully matured and exhibited no atypical features. A typical appearance of acromegaly, frontal bossing, prominence of the jaw and bony overgrowth and cutaneous changes of acanthosis nigricans on the neck, the axillae and the groins were observed. Growth hormone hypersecretion and insulin resistance were detected in the patient. A pituitary tumor was found and resected surgically. After the operation, endocrinological abnormalities and cutaneous manifestations of acanthosis nigricans improved markedly. As far as we know, this is the first report of the coexistence of urticaria pigmentosa, acromegaly and acanthosis nigricans.