Bone Marrow Examination

Acquiring a sample

The assessment of bone marrow is critical to making a diagnosis of a myelodysplastic syndrome, and provides an important diagnostic role in the investigation of anemias and pancytopenias.

A bone marrow examination is a routine procedure that can ordinarily be undertaken in the outpatient setting. There are two approaches, which might be undertaken together or separately. The first is the bone marrow aspiration which involves placing a needle through the bone and withdrawing a small volume of cells. The second is the trephine biopsy, which involves a larger needle and excises a shaft of bone marrow in an attempt to preserve its structural integrity.

Analyzing and classifying a sample

The results of these acquisitions may involve direct microscopy using stains or other chemicals / biological agents to identify specific types of cell. In this way, it is possible to comment on the types of cell present or absent, but also on the appearance or response of the cells to staining. Cytogenetic studies are also an increasingly important technique.

Typical morphological abnormalities in MDS include the presence of megaloblasts, dissociated maturation of the nucleus and cytoplasm, abnormal multinucleated erythroblasts and ringed sideroblasts, hyper- or hypo-segmented neutrophils, reduced or missing granules as well as many other abnormalities.1

The classification of MDS is based (in part) on the results of the bone marrow examination1 which itself is important in issuing a prognosis.2

Box: Classification and stratification in MDS

Classification systems
- French-American-British (FAB)
- World Health Organization (WHO)

Risk-stratification systems
- International Prognostic Scoring System (IPSS-R); used only at diagnosis
- WHO classification-based Prognostic Scoring System (WPSS); used at any time during the disease course
- MD Anderson Cancer Center (MDACC); used at any time over the disease course

Next: Cytogenetics


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  1. Yoshida Y. Physician Education: Myelodysplastic Syndrome. Oncologist. 1996;1(4):284-287.  
  2. Greenberg P, Cox C, LeBeau MM, et al. International scoring system for evaluating prognosis in myelodysplastic syndromes. Blood. 1997;89(6):2079-2088.