Xanthoma disseminatum, a rare cause of diabetes insipidus

A 33-yr-old male developed typical symptoms and findings of diabetes insipidus. A computed tomographic scan of the hypothalamus/pituitary was normal, and he was diagnosed as having idiopathic diabetes insipidus. At age 38 yr, he developed two 1- to 2-mm reddish papules on his skin. Biopsy revealed infiltrative histiocytes laden with lipid. Bone scans and bone x-rays showed widespread osteolytic and osteoblastic disease. The disease was diagnosed as a rare disseminated histiocytic disorder, xanthoma disseminatum. A classification of histiocytic disease is presented.