Case for diagnosis
A 72-year-old man in complete remission of an immunoglobulin G kappa multiple myeloma.\nTen months later he presented firm painful erythemato-violaceous or flesh color nodules\nand tumors on the trunk, axillae and face ( and ). The patient referred\nconcomitantly asthenia and fever for 3 days. An incisional biopsy showed a dense\ninfiltrate of plasmablasts in the dermis and hypodermis (). The immunohistochemistry evidenced a dense infiltrate of\nmonoclonal plasma cells expressing kappa light chains, strongly positive for CD138\n(). Serum immunoelectrophoresis\nidentified monoclonal IgG 2152 mg/dL (700-1600 mg/dL) and κ chains 702 mg/dL (170-370\nmg/dL). Urine immunoelectrophoresis showed monoclonal κ chains: 0,925 mg/24h (0-0,7 mg).\nBone marrow biopsy evidenced plasmocytosis with cellularity of almost 100%.