Nonsecretory multiple myeloma.
Among 186 patients with multiple myeloma (MM), five women were diagnosed as having MM without M-component in serum and or urine at the diagnosis and along the evolution. Bone marrow plasmacytosis at greater than 30% was found in all patients and bone x-rays showed lytic lesions in all but one case, osteoporosis in all, and pathologic fractures in two. Serum electrophoresis showed a striking hypogammaglobulinemia in all, and polyclonal immunoglobulin levels were markedly reduced. The immunofluorescence of plasma cells in bone marrow was positive for monoclonal light chain polypeptides in four patients, and the ultrastructure showed mature plasmocytes with a wide rough endoplasmic reticulum (RER) and an intact Golgi apparatus. In three patients, therapy with melphalan plus prednisone was started. The remaining two were treated with an M-2 protocol. Death was an early event in two patients; the response was good in the remaining patients, without differences regarding secretory MM. Despite some reports stressing an unfavourable prognosis in MM without M-component, in our series it is roughly the same as in MM with secretion.