Necrobiotic xanthogranuloma with IgA paraproteinemia and extracutaneous involvement.

Numerous nodular xanthomatous lesions arose, gradually increasing in number on the back, chest, lips, tongue, and exposed "V" area of the chest on a 78-year-old man. Painful oral nodules and hoarseness developed subsequently. Histologic examination of the skin revealed a suppurative and granulomatous inflammation with an accumulation of acute polymorphonuclear neutrophils, nuclear dust, and xanthomatous histiocytes. Giant cells were rare and cholesterol clefts were absent. Biopsy of the oral mucosa and the larynx showed a similar process. Direct immunofluorescence was positive for vascular immune reactants at the basement membrane and fibrin in between collagen bundles. The patient had a serum IgA level of 432 mg/dl (normal level, up to 380), with normal IgG and IgM serum concentrations. A Raji cell assay was 240 micrograms/AHGEQ/ml (normal less than 5). CH-50 was decreased and C2, C4, and C3 were within normal limits. The dermatopathology was initially thought to be consistent with erythema elevatum diutinum, and the patient was treated with dapsone and prednisone, with a marginal response. There were no dermatopathologic findings of vasculitis. On review, the patient's dermatopathology was more consistent with necrobiotic xanthogranuloma (NXG). To our knowledge, this is the first report of an association of NXG with an IgA gammopathy and the second reported case of extracutaneous involvement with NXG.