Periorbital necrobiotic xanthogranuloma and stage I multiple myeloma. Ultrastructure and response to pulsed dexamethasone documented by magnetic resonance imaging.

We observed a 40-year-old woman with necrobiotic xanthogranuloma from the inception of indurated eyelid and periorbital infiltrates and concurrent stage I multiple myeloma to resolution of infiltrates in skin and bone marrow after pulsed high-dose oral dexamethasone therapy. Ultrastructural studies revealed lipid vacuoles in epidermal keratinocytes, in dermal histiocytic macrophages, and in vascular and lymphatic endothelial cells. The presence of lipid vacuoles in epidermal keratinocytes has not been reported previously in xanthogranuloma.