Treatment of necrobiotic xanthogranuloma with 2-chlorodeoxyadenosine

A 71-year-old man presented with ulcerating yellow-red plaques of the back, chest, face, and extremities (Figure 1). He had a 10-year history of these lesions. The initial plaque appeared on the back followed by rapid progression of multiple similar lesions involving the face, chest, abdomen, and extremities. The plaques on his face were predominately in the periorbital and eyelid regions. Skin biopsy revealed an ulcerated epidermis. Dense sheets of foamy histiocytes were present in the dermis and contained foci of necrobiosis. Numerous Touton giant cells were present and cholesterol clefts were prominent. Special stains for organisms were negative. On further laboratory evaluation, serum protein electrophoresis revealed a monoclonal spike of 0.5 g/dL IgG lambda. Results from bone marrow biopsy were negative. Other significant laboratory findings included an elevated sedimentation rate and low serum complement. Clinical findings, histopathology, and laboratory evaluations were consistent with the diagnosis of necrobiotic xanthogranuloma (NXG).