Elderly man with a pulmonary mass and osteolytic lesions: is it primary pulmonary plasmacytoma or multiple myeloma with an extramedullary pulmonary nodule?

The presence of these plasma cells could mean primary pulmonary plasmacytoma or multiple myeloma with extramedullary pulmonary dissemination. [...]all patients must be evaluated for multiple myeloma with (1) tests for classical CRAB symptoms: hypercalcaemia, renal impairment, anaemia or bone abnormalities; (2) bone marrow study for monoclonal plasma cells occupying >10%; and (3) presence of monoclonal protein in serum or urine or, in non-secretory multiple myeloma, >=30% monoclonal plasma cells in bone marrow, is required.