Cutaneous disseminated xanthogranuloma in an adult: case report and review of the literature.

Xanthogranuloma (XG) is a rare, non-Langerhans cell histiocytosis (LCH) that most commonly presents in infancy or early childhood. The condition is typified by the formation of reddish to yellow papules and nodules that are usually solitary. Xanthogranuloma rarely occurs in adults with immunohistochemical features similar to those seen in juvenile XG. Lesions in the adult form seen in juvenile XG. Lesions in the adult form also are typically solitary. We describe a 70-year-old white man who presented with widespread flat-topped, reddish to yellow papules and nodules with histologic and immunohistochemical findings consistent with XG. We explore the pathogenesis, differential diagnosis, prognosis, and treatment of this rare eruption. Comparison of adult and juvenile XG will facilitate a better understanding of the disease. Although rare, XG is an important disease to consider in the differential diagnosis of xanthomatous disease in adults.