Necrobiotic Xanthogranuloma

Eight patients who developed unusual xanthomatous plaques with a tendency to ulceration and scarring and subcutaneous extension are described. Six patients had an IgG monoclonal serum paraprotein. Two patients had multiple myeloma and one patient had a plasmacytic lymphoma. Neutropenia, hypocomplementaemia and cryoglobulinaemia were variable features. Sixteen skin biopsies showed a consistent pattern of xanthogranulomatous nodules separated by zones of necrobiosis and an admixture of prominent giant cells. Lymphoid or plasma cell nodules may occur in the biopsies. Necrobiotic xanthogranuloma belongs to a range of xanthomas which has been associated with dysproteinaemia and lymphoreticular malignancy.