[Necrobiotic xanthogranulomatosis: a cutaneous manifestation of a monoclonal IgM gammopathy]

Necrobiotic xanthogranulomatosis is a rare cutaneous disorder usually associated with monoclonal gammopathy. Most frequently, cutaneous lesions involve the face (periorbital region) and the trunk, and are characterized by indurated xanthomatous plaques and nodules.We describe a patient presenting with necrobiotic xanthogranulomatosis that was unusual, as it was associated with IgM kappa monoclonal gammopathy of undetermined clinical significance and because no periorbital involvement was observed.Necrobiotic xanthogranulomatosis should be distinguished from other cutaneous manifestations associated with plasma cell dyscrasias, such as normolipemic plane xanthoma. It can be associated with IgM gammopathy.