Diffuse primary plasmacytoma of the lung

Primary plasmacytoma of the lung is a rare tumor, thus presenting a diagnos tic challenge to the clinician. So far, approximately 20 cases have been ve rified by immunohistochemistry. We describe an elderly patient presenting w ith progressive dyspnea on exertion, dry cough, weight loss and malaise. Th e main finding on plain chest radiography was a diffuse infiltration of pul monary parenchyma in the lower parts of both lungs and in the middle part o f the right lung. The histology of the open lung biopsy of the right middle lobe revealed massive and diffuse infiltration by well differentiated plas ma cells with extracellular deposits of amyloid. The plasma cells and amylo id expressed a monoclonal lambda light chain. No monoclonal spike was shown by serum and urine immunoelectrophoresis. A skeletal survey and bone marro w biopsy specimen excluded a disseminated disease and a diagnosis of extram edullary plasmacytoma was made. The patient was considered for VI courses o f VMCP chemotherapy after which a complete regression on chest roentgenogra phy was evident. Almost five years after the diagnosis the patient is still alive without any evidence of disease recurrence or dissemination.