Nonsecretory multiple myeloma.

A diagnosis of nonsecretory multiple myeloma, based on multiple bony lytic lesions seen on roentgenographic studies and sheets of plasma cells seen in the bone marrow, was established in two patients with severe back pain. No paraprotein was detected in the serum or concentrated urine of the patients. Immunofluorescent staining of the bone marrow demonstrated the presence of intracytoplasmic J chains in the patients' plasma cells.