Bone marrow biopsy
One of the most frequent hematological investigations ordered in leukemia is a bone marrow biopsy. Since bone marrow is the leading manufacturing plant of blood cells, and since it is hidden under a layer of thick bone, we need special techniques to obtain a sample for investigations. After birth, and as the human advances in age, the percentage of the active “red” marrow decreases. By late childhood and early adulthood, it becomes almost entirely replaced by the inactive “yellow” marrow, and the active marrow becomes limited to the axial bones especially the sternum, ribs, hip bone and the proximal ends of long bones -the parts near the center of the body-.
Bone marrow biopsy is ordered for the following conditions:
- Unexplained anemia decreased platelets or even increased white blood cells.
- The diagnosis, staging, and monitoring of the treatment of hematological malignancies whether leukemias, myelodysplastic disorders, lymphomas or multiple myeloma.
- Fever of an unknown origin.
- Some rare metabolic diseases as Nieman-Pick and Gaucher.
- Metastatic cancers from elsewhere in the body and staging of other granulomatous diseases as sarcoidosis and tuberculosis.
There are two main types of bone marrow biopsy: aspiration and trephine biopsy. In bone marrow aspiration, the doctor will push a needle through the thick bone -under local anesthesia- and then aspirate a small amount of the marrow. This procedure is used in case of some bone cancers to get a general look at the cellular components of the bone marrow. Trephine bone marrow biopsy, on the other hand, involves the sampling of a small part of the cortical bone with the marrow underneath with a special needle and technique. It is more accurate than bone marrow biopsy and is the only option in cases where bone marrow aspiration cannot be done as in cases of aplastic anemia and metastatic cancers.