Sandbox/am

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Plasma cell myeloma is a monoclonal neoplastic proliferation of plasma cells of bone-marrow derivation, usually multicentric, that eventually infiltrates various organs but rarely produces plasma cell leukaemia. It is characterized by osteolytic lesions, bone pain, hypercalcemia, a monoclonal gammopathy, and disorders due to depositon of abnormal immunoglobulin chains (amyloid) in various tissues including kidney. It ranges from MGUS to plasmacytoma to multiple myeloma. Solitary plasmacytoma is a rare plasma cell disorder, accounting for 2–10% of plasma cell disorders. It is classified as either solitary extramedullary plasmacytoma (SEP) or solitary bone plasmacytoma. The head and neck are the predominant sites for SEP, and only a small number are associated with serum Most extramedullary plasmacytomas respond to local radiotherapy and have a good prognosis. Although the most common plasma cell dyscrasia is monoclonal gammopathy of undetermined significance (MGUS), closely related disorders include multiple myeloma, solitary plasmacytoma of bone, extramedullary plasmacytoma, waldenstorm's macroglobulinemia, Amyloidosis, light chain deposition disease, paraproteinemia and heavy chain disease.,. The spectrum of MGUS, solitary plasmacytoma of bone, and asymptomatic and symptomatic multiple myeloma may actually represent a natural progression of the same disease. Prognosis and outcome of PCM, commonly known as multiple myeloma (MM)—the most prevalent and fatal PCN and the second most common hematologic malignancy worldwide—remain grim despite availability of sophisticated conventional treatment protocols (chemotherapy, irradiation, hematopoietic stem cell transplantation) that have been recently supplemented by novel targeted therapies including proteasome inhibitors (bortezomib), immunomodulatory agents (thalidomide, lenalidomide), antibodies to interleukin-6 (IL-6) or its receptor, and a variety of newly emerging inhibitors of cellular signal transduction pathways

Causes

Although the exact cause isn't known, doctors do know that plasma cell neoplasm begins with one abnormal plasma cell in your bone marrow — the soft, blood-producing tissue that fills in the center of most of your bones. This abnormal cell then starts to multiply. Because abnormal cancerous cells don't mature and then die as normal cells do, they accumulate, eventually overwhelming the production of healthy cells. In healthy bone marrow, less than 5 percent of the cells are plasma cells. But in people with multiple myeloma, more than 10 percent of the cells may be plasma cells.Because myeloma cells may circulate in low numbers in your blood, they can populate bone marrow in other parts of your body, even far from where they began. Uncontrolled plasma cell growth can damage bones and surrounding tissue. It can also interfere with your immune system's ability to fight infections by inhibiting your body's production of normal antibodies.

Natural history and complication

The spectrum of MGUS, solitary plasmacytoma of bone, and asymptomatic and symptomatic multiple myeloma may actually represent a natural progression of the same disease. So the complication of Mgus could be multiple myeloma or death as the disease progress from one end of the spectrum to another.

Laboratory findings :

The presence of unexplained anemia, renal dysfunction, a high (ESR), lytic bone lesions, elevated beta globulin, and/or a high serum protein (especially raised globulins or immunoglobulins) may prompt further testing

MRI

An MRI can be useful to identify additional unsuspected plasma cell lesions which do not appear on skeletal surveys.