The Bone Marrow Biopsy Test Report


Bone Marrow 101

You may wonder why bone marrow needs to be biopsied in the first place. The marrow is the spongy inner part that is present in most of the large bones in the human body. Once a baby is born, the bone marrow essentially becomes the factory that produces a person’s red blood cells, infection-fighting white blood cells, and platelets to help blood clot. When doctors find or initially suspect a that a person may have a cancer of the blood cells, also called a hematologic malignancy, they often need to go to the blood cell factory -- the source -- to figure out what kind of blood cancer it is.

The Bone Marrow Biopsy

The procedure consists of drawing up the liquid, termed aspiration, and the biopsy itself, which involves taking a sample of the solid bone marrow.

May Provide Information About…

·       How well is my bone marrow functioning?

·       Why do I have a low red blood cell count, or anemia?

·       Why do I have a low number of white blood cells, or leukopenia?

·       Why do I have a low number of platelets, or thrombocytopenia?

·       If I have lymphoma, has it spread to the bone marrow?

·       If I have lymphoma or leukemia, what type do I have?

Stored iron within the marrow can also be assessed.

The Bone Marrow Report

Are the Normal Proportion of Cells Present?

The normal marrow contains different types of cells. Some become red blood cells, some white blood cells and some platelets. Certain disorders result in proportions of these cells in the marrow that are different from normal.

This finding can be verified by a bone marrow aspiration test.

·       Reports may contain information and nomenclature that refers to the lineage or family tree for a given cell. For instance, the “erythyroid series,” the “myeloid series” and the “megakaryocytic series” all refer to steps cells go through to become red blood cells, white blood cells and platelets, respectively.

The monocytic series refers to monocyte white blood cells.

·       Other tools may also be used to answer questions about the proportions of cells. For instance the M:E ratio reports the ratio of all granulocytic plus monocytic cells (Myeloid) to all erythroblasts (Erythroid).

·       Bone marrow cellularity refers to how “beefy” or robust the factory looks on microscopic examination; in order to assess a person’s cellularity, the pathologist must know the individual’s age – normal cellularity differs quite remarkably, for instance, between a child and a 75 year old, with the older individual normally having less cellularity.

Are Abnormal Marrow Cells Present?

In addition to the light microscope, bone marrow may be examined using something called flow cytometry, which is a higher-tech way of picking out and sorting cell counts. Chromosomal analysis and polymerase chain reaction, or PCR, can also be done.

Cells that develop into different blood cells go through a process of development in the bone marrow. Immature cells gradually change into mature cells that are released in blood. In some marrow disorders and in leukemias the number of immature cells, or blast cells, increase substantially in number.

In another cancer called multiple myeloma, cells called plasma cells increase greatly in number within the marrow. Lymphomas can also involve the bone marrow and can appear as leukemia-like illnesses. This can also show up in a bone marrow test.

Are Metastatic Cells Present?

Lymphomas and a variety of other cancers can spread to the bone marrow, as well as to other organs of the body. When a lymphoma or hematologic malignancy spreads to the bone marrow, it is not usually referred to as metastasis.  Instead, it might be called disease extension or secondarily extranodal lymphoma or lymphoma with bone marrow involvement.

Other cancers can also spread to the bone marrow, and when this occurs, such as in the spread of lung cancer or prostate cancer, the involvement at the bone marrow definitely is referred to as metastatic disease. A bone marrow test can identify cancer cells in the marrow and diagnose a metastasis.

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