Letter: Necrobiotic xanthogranuloma of extremities in an elderly patient successfully treated with low-dose prednisolone

We describe a 93-year-old Japanese woman who developed a painful yellowish plaque with reddish border on her left lower leg. Histological evaluation demonstrated hyaline necrobiosis and granulomatous lesions composed of histiocytes (some with foamy cytoplasm), multinucleated giant cells, and numerous cholesterol crystals. Serum electrophoresis displayed the presence of an M-peak with IgG λ paraproteinemia. There was progressive ulcer formation in the location of the biopsy on the left leg. Multiple tender red dermal and subcutaneous skin nodules developed on her extremities. Oral administration of prednisolone 20 mg daily (0.5 mg/kg) was started. After 4 weeks, she obtained resolution of the skin lesions.