Nonsecretory multiple myeloma

Abstract

Multiple myeloma is characterized by clonal proliferation of plasma cells usually of the B cell type. The skeletal manifestations are usually osteolytic lesions whose differential diagnosis includes primary and secondary bone tumor. This tumor is characterized by the presence of abnormal paraprotein 8 in blood and urine. However, one to five per cent of the cases do not have any protein. Hence they are termed nonsecretory. It often poses a diagnostic dilemma when it is presented to orthopedic surgeons with no clear features of the disease. Our case report exemplifies such a diagnostic dilemma. A high index of suspicion must be borne in mind when excluding multiple myeloma as a cause of pain, pathological fracture or lytic lesion.

Oligosecretory multiple myeloma: a case report

“…The diagnosis of NSM depends on the demonstration of clonal/atypical plasma cells in bone marrow aspiration, bone marrow biopsy, or biopsy of the osteolytic lesion [ 2 7 8 ]. In our case, bone marrow aspirates from the posterior superior iliac spine contained excess plasma cells, and permeative lesions were observed in the pelvis.…”

“…The prognosis for patients with NSM has been a subject of debate in the available literature [ 1 2 7 9 ]. Albumin levels are not decreased, and thus, the NSM infection rate is lower than that for secretory myelomas.…”

“…TO THE EDITOR: Approximately 95–97% of myelomas are of the secretory type, i.e., they exhibit monoclonal (M) band in the γ region on either urine or serum protein electrophoresis [ 1 2 ]. Non-secretory myelomas were first described in 1958 by Serre, and they constitute 1–5% of myelomas.…”

Non-secretory multiple myeloma: from biology to clinical management

“…Such rare patients would not be able to be monitored by either traditional methods or intracellular immunofluorescence, which can be used to detect monoclonal Ig in the cytoplasm of many cases of NSMM. It is hypothesized that the mechanism of non-production is the loss of SFLC secretion by MM clones, which were initially FLC secretors, although this has not been definitively proven.True non-secretors: These MM cells produce Ig molecules but are unable to secrete them (the variety of mechanisms by which this occurs is discussed in detail in the following) 10,21

False non-secretors: Initially Decourt et al21 and since then others have referred to certain cases as “false non-secretors.” These are MM variants or related plasma cell diseases that had measurable intracellular Ig by immunofluorescence but no measurable extracellular component by typical testing, despite clear pathological evidence that they were being secreted (such as Ig deposits found in renal biopsies, as can be found as part of the recently described entity monoclonal gammopathy of renal significance) 21–23.

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“…True non-secretors: These MM cells produce Ig molecules but are unable to secrete them (the variety of mechanisms by which this occurs is discussed in detail in the following) 10,21…”