18F-FDG PET/CT in Xanthoma Disseminatum.

A 64-year-old woman who had yellowish orange-colored, sharp-edged, and flat skin plaques and back pain for about a year was referred for(18)F-FDG PET/CT imaging and her bone marrow biopsy revealed 10% to 20% atypical plasma cells suggestive of monoclonal gammopathy. PET/CT showed linear(18)F-FDG uptake on the surface of the skin on the neck, axillary, chest, inframammary, and inguinal regions. Punch biopsy revealed numerous histiocyte infiltrates with large vacuoles, xanthomized cytoplasm in the dermis, and midsection, and there are several Touton-type giant cells supporting the preliminary diagnosis of xanthoma disseminatum.