The combined examination of blood smear, bone marrow aspirate smears, and biopsy(ies) is paramount in the diagnosis and classification of MDS. The evaluation for the presence of abnormal cytogenetics is also valuable.
The bone marrow aspirate and biopsy show increased cellularity with granulocytic proliferation. The dysplastic features in MDS are observed in one or more of the myeloid cell lines. The recommended requisite percentage of cells manifesting dysplasia, to qualify as significant, is 10% of the specific cell line. Definitions of cellular dysplasias found in MDS are as follows:
- Dysplastic erythroid cell line (due to dyserythropoiesis)
- Dysplastic granulocytic cell line (due to dysgranulopoiesis)
- Dysplastic megakaryocytic (due to dysmegakaryopoiesis)