Scrotal calcinosis: idiopathic or dystrophic?

Scrotal calcinosis is a rare benign local process characterized by multiple, painless, hard scrotal nodules in the absence of any systemic metabolic disorder. Histological examination reveals extensive deposition of calcium in the dermis, which may be surrounded by histiocytes and an inflammatory giant cell reaction. Numerous theories have been propounded to explain the pathogenesis of this condition, but the principal debate revolves around whether the calcium is deposited at the site of previous epithelial cysts or the calcified nodules are purely idiopathic. This is the largest study of scrotal calcinosis to date with 100 cases, on which clinical, biochemical, radiological, cytopathological, and histopathological examinations were conducted. The histological picture shows a continuous spectrum of changes ranging from intact epithelial cysts (41.0%) - both normal and inflamed; through inflamed cysts containing calcific material in the lumen but with intact cyst wall (53.0%); calcified inflamed cysts with partial epithelial lining (11.0%); to 'naked' calcium deposits lying in the dermis (100%), sometimes compressing surrounding collagen fibres to form a pseudocyst (56.0%). The presence of normal values of calcium and phosphorus along with this spectrum of changes in histology both support the theory that these form by dystrophic calcification of epithelial cysts in a progression that involves inflammation, rupture, calcification and obliteration of the cyst wall.