Lipid and giant cell poor necrobiotic xanthogranuloma

An 88-year-old man over a 7-month period developed multiple yellow firm focally ulcerative papules and nodules over his face, neck and forearms. Seven skin biopsies showed a diffuse infiltrate of epithelioid histiocytes associated with areas of necrosis with neutrophilia. Two biopsies showed xanthogranulomatous foci, but cholesterol clefts, prominent giant cells or lymphoid aggregates were not evident. Necrosis with leukocytoclastic debris overshadowed the presence of hyaline necrobiosis. Ultrastructural examination and oil red-o stains on frozen sections revealed focal lipid vacuoles within histiocytes. A paraprotein was detected in the patient's serum. This presentation may represent a lipid and giant cell poor variant of necrobiotic xanthogranuloma (NXG) and may potentially lead to a delay in diagnosis.