Idiopathic calcinosis of the scrotum: histopathologic observations of fifty-one nodules.

A 29-year-old man had a 2-year history of multiple, asymptomatic, firm, subcutaneous nodules on the scrotal skin, which sometimes discharged a chalky material. Fifty-one nodules were observed in the histopathologic examination, which revealed, in addition to the typical findings of idiopathic calcinosis of the scrotum, various forms of intact cysts: epidermal (some calcified), pilar (calcified), hybrid (calcified), and indeterminate cysts with diffusely calcified keratinous content and attenuated walls. A mixture of calcified keratinous material and inflammatory infiltrates was detected, with or without remnants of the cyst wall. These findings suggest that idiopathic calcinosis of the scrotum derives from the dystrophic calcification of cysts.