The bone marrow biopsy (BMB) is the definitive test for confirming the diagnosis of WM.
This procedure can be performed in a physician’s office or in a monitored setting (such as a hospital) under local anesthetic or light sedation. The specimen is usually obtained from the posterior iliac crest (back of the hip bone) by using a large-bore needle, although in some cases it may be taken from the sternum (breast bone) or other bones.
Both a liquid bone marrow sample (bone marrow aspiration) and a solid bone sample (bone marrow biopsy) may be taken during the procedure.
A pathologist examines the bone marrow cells under a microscope and may also perform additional testing with special stains, flow cytometry, or FISH analysis to further identify the type of cancer cells present.
In WM, the pathologist will note an increased amount of lymphoplasmacytic cells (which have features of both lymphocytes and plasma cells) and estimate the amount of infiltration of these cells into the bone marrow. He will also examine the marrow to determine how healthy it is and whether it appears capable of generating adequate amounts of normal blood cells.
Even with the sedation, a patient may experience brief pain during the procedure and some soreness in the biopsy area afterwards when the numbing medicine wears off. Most patients can go home right after the procedure.
Because a bone marrow biopsy is a costly and invasive technique, frequent biopsies are not usually recommended for disease monitoring.