Xanthoma disseminatum with asymptomatic multisystem involvement

Xanthogranulomas belong to non-Langerhans histiocytosis of the second group in the Histiocyte Society classification. They comprise a heterogeneous group of rare entities frequently involving cutaneous tropism. Xanthoma disseminatum belongs to this group of non-Langerhans histiocytosis. We report a case of xanthoma disseminatum (XD) in which localized skin and mucous impairment revealed multisystem involvement. A 28-year-old man presented with a two-year history of progressive yellow-orange and infiltrated xanthomatous papulonodular lesions of the face. Lesions of the oral mucosa and genital region were seen, with no functional repercussions. No ophthalmic or other complications were found. Histopathology showed a dense histiocytic infiltrate within the dermis with Touton giant cells, foamy multinucleated giant cells and inflammatory cells, without necrobiosis. Histiocytes were positive for CD68 but negative for CD1a. Gastric and lung involvement was seen and was confirmed at histology. Bone scintigraphy showed suspicious left ulnar hyperfixation suggesting bone involvement. No monoclonal gammopathy or diabetes insipidus was seen. Our patient was treated with corticosteroids 1mg/kg/day and thalidomide 100 mg/day. The outcome was marked by regression and exfiltration of the cutaneous lesions from the second week of treatment, with subsidence continuing at 3 months. This case involves a very rare form of xanthoma disseminatum. The localized facial skin lesions revealed multifocal non-Langerhans histiocytosis that was in fact asymptomatic. The diagnosis of XD was based on clinical, histological and immunohistochemical criteria. Xanthoma disseminatum is a non-Langerhans histiocytic proliferation first described by Montgomery in 1938. This rare entity is characterized by skin and mucous membrane xanthomatosis in which the facial involvement is common, together with diabetes insipidus and normal lipid metabolism. The prognosis is determined by the presence of mucosal xanthomas and visceral involvement. Thus, all xanthogranulomas involving multiple lesions warrant screening for visceral involvement. Diagnosis of this entity can be difficult and is usually based on clinical and histopathological findings. In addition, treatment is complex and non-consensual.