Resident Rounds: Part III
Necrobiotic Xanthogranuloma of the Extremities

January 2012 | Volume 11 | Issue 1 | Features | 122 | Copyright © January 2012



A 64-year-old gentleman presented with a six-year history of non-healing cutaneous ulcers. He described multiple painful lesions on his extremities, which manifested as red firm papules or nodules that sometimes ulcerate. Medical history was also significant for iritis and vestibular dysfunction. Examination showed multiple ulcerations with indurated erythematous to violaceous borders. On the right posterior calf, there were coalescing indurated xanthomatous plaques (Figure 1a). Laboratory investigations were remarkable for a weakly positive ANA, strongly positive SS-A/Ro antibody, decreased C4, polyclonal hyergammaglobulinemia and monoclonal IgM kappa proteinemia.
Multiple skin biopsy specimens revealed superficial and deep dermal granulomatous inflammation with necrobiosis, and numerous Touton and foreign body-type giant cells (Figure 1b). The histological pattern was interpreted as most consistent with necrobiotic xanthogranuloma (NXG). Colloidal iron stain highlighted focal dermal mucin. GMS and AFB stains were negative for microorganisms. Evaluations in Rheumatology, Neurology and Dermatology resulted in the diagnoses of NXG, Sjögren’s syndrome, vasculitic neuropathy and monoclonal IgM kappa gammopathy. Intravenous immunoglobulin (IVIG) was recommended as treatment for both NXG and vasculitic neuropathy, but after one dose of IVIG the patient developed icteric, hyperbilirubinemic hemolytic anemia, which mandated discontinuation of therapy. Aquacel AG was used for local wound care and the cutaneous ulcers showed partial healing in the absence of systemic therapy.
Necrobiotic xanthogranuloma is a histiocytic disease characterized by destructive cutaneous lesions and associated monoclonal paraproteinemia. This case is unusual in several respects. First, lesions of NXG are not typically restricted to the extremities. Lesions most commonly involve periocular skin, frequently with ophthalmic complications.1-3 In a 2009 review by Wood, et al.,