Extramedullary plasmacytoma.

Extramedullary plasmacytoma is a rare form of plasma cell dyscrasia, in which malignant plasma cell tumors arise outside the bone marrow. The tumor may arise in any part of the body but the vast majority occur in the head and neck, primarily in the nasal cavity, paranasal sinuses, or upper airway. Six patients with extramedullary plasmacytoma are presented and the clinical and radiographic findings are reviewed.