Objective: To report a case of a young normolipidemic woman with mucocutaneous xanthomas who developed neurogenic diabetes insipidus and hyperprolactinemia because of an inflammatory pituitary stalk lesion. Methods: The clinical features, laboratory results, magnetic resonance imaging, and pathology findings are presented. In addition, the pertinent literature is reviewed. Results: A 23-year-old woman presented with a 9-month history of polydipsia, polyuria, galactorrhea, secondary amenorrhea, and weight gain. Her previous medical history included chronic anemia and widespread mucocutaneous xanthomas. Laboratory tests showed hyperprolactinemia, normal electrolytes, and a normal lipid profile. The results of a water deprivation test were compatible with neurogenic diabetes insipidus, and cerebral magnetic resonance imaging showed pituitary stalk thickening. Histologic findings on a skin biopsy specimen supported the diagnosis of non-Langerhans histiocytosis. Treatment was initiated with cabergoline, nasally administered desmopressin, radio-frequency ablation of facial skin lesions, and surgical excision of other accessible lesions. Conclusion: Xanthoma disseminatum is a rare, benign proliferative disorder characterized by extensive cutaneous and mucous membrane xanthomas in normolipidemic patients. Central nervous system involvement is rare and usually occurs in the systemic variety. Pituitary stalk disease commonly causes hyperprolactinemia, diabetes insipidus, and various degrees of hypopituitarism. The natural history of xanthoma disseminatum usually is benign, but lesions in critical anatomic sites may result in morbidity and mortality. Copyright © 2010 AACE.