Nonsecretory multiple myeloma.

Nonsecretory multiple myeloma (NSMM) is a rare variant of the classic form of multiple myeloma (MM) and accounts for 1% to 5% of all cases of MM. The clinical presentation and radiographic findings of NSMM and MM are the same. The diagnosis of MM requires the detection of a monoclonal gammopathy in the serum or urine. In NSMM, however, no such gammopathy can be demonstrated, making the diagnosis more difficult. We describe a 43-year-old African American woman who initially had back pain and pathologic vertebral compression fractures that were thought to be due to osteoporosis. Five months later, hypercalcemia developed and NSMM was diagnosed. No monoclonal gammopathy was found in the serum or urine, but skeletal survey showed diffuse osteolytic lesions, and bone marrow biopsy revealed marked plasmacytosis. The immunohistochemical techniques and chromosomal analysis methods that are currently available are discussed.