FDG PET/CT depicts cutaneous plasmocytoma.

A 63-year-old man with a 1-year course of IgA-λ multiple myeloma (MM) and a history of autologous stem cell transplantation presented with multiple nontender, nodular violaceous skin lesions that were located predominantly on his trunk. Diagnostic workup using F-FDG PET/CT revealed disseminated disease including highly hypermetabolic (sub)cutaneous lesions, consistent with active manifestations of MM. Histopathology confirmed monoclonal, λ-restricted plasma cell infiltrates with a high proliferation index (Ki-67) of about 80%. Cutaneous manifestation of MM is an uncommon observation in clinical practice portending poor prognosis.