Weatherly's Woes - Plasma Cell Neoplasms

MULTIPLE MYELOMA

Plasma Cell Cancer

Multiple Myeloma is cancer of plasma cells. Plasma cells normally live in the marrow, which is a really smart idea since it’s so sheltered. After all, they have to live such a long time. MM is really common -- about 1% of all malignancies and 10% of all heme cancers. Here’s a diagram showing most of the big problems with MM, which are mostly due to the broken IgG and IgA that it pumps out, plus the fact that they stimulate Osteoclasts (presumably to make room for themselves in the marrow).

MM plasma cells produce monoclonal Ig (identical useless light chains), which can be detected on labwork as an elevated serum protein level. A mysteriously elevated protein should warrant a Serum Protein ElectroPhoresis (SPEP) test. It highlights the different proteins in the blood by graphing them on a chart. Albumin is normally the tallest peak on the graph since it’s the most numerous protein, and the Gamma peak (all the Igs) is typically the next tallest peak. In MM, they have lots of monoclonal Igs, which looks like a tall skinny spike on the SPEP graph (called an M spike). An M spike indicates monoclonal immunoglobulin. Note that the term M spike is potentially confusing, as the M in M Spike doesn’t stand for IgM. Actually, MM usually has lots of IgG or IgA! Patients with MM lose antigenic diversity, and usually die from infection. The bone marrow crowding also blocks erythropoiesis, resulting in some anemia. Dim prognosis.

Protein electrophoresis

This is a Plasma cell. You have to recognize images of them. They crowd the marrow in MM.

Coin stacking RBCs (Rouleaux formation)

Monoclonal Gammopathy of Undetermined Significance - the patient has labs that suggest MM, but without any of the symptoms. 1% may progress to MM

Waldenstrom Macroglobulinemia - cancer of plasma cells that make IgM (instead of IgG like MM). IgM is a huge protein. It turns the serum hyperviscous (thick as mud), which causes blood clots, headache, blurry vision, Raynaud phenomenon and retinal hemorrhages. You don’t see any of the bone lesions, amyloidosis or renal symptoms that define MM.