Peripheral Smear Findings in Myelodysplastic Syndromes

Key Morphologic Features by Cell Line

The American Society of Hematology recommends evaluation of dysplastic features across one or more cell lines, including erythroid abnormalities (anisocytosis, poikilocytosis, basophilic stippling), myeloid abnormalities (pseudo-Pelger-Huët cells with nuclear hypolobation, hypogranulation/degranulation), megakaryocytic abnormalities (platelet anisocytosis, giant platelets), and potentially circulating blasts 1
Erythroid dysplasia is characterized by anisocytosis (variation in red cell size) 1
Erythroid dysplasia is also characterized by poikilocytosis (variation in red cell shape) 1
Erythroid dysplasia is characterized by basophilic stippling 1
Myeloid dysplasia is characterized by pseudo-Pelger-Huët anomaly: granulocytes with nuclear hypolobation (bilobed or monolobed nuclei resembling pince-nez eyeglasses) 1, 2
Myeloid dysplasia is characterized by cytoplasmic hypogranulation or complete degranulation of granulocytes 1, 2
Circulating blasts may be present and must be enumerated 1, 3
Megakaryocytic dysplasia is characterized by platelet anisocytosis (variation in platelet size) 1
Megakaryocytic dysplasia is characterized by giant platelets 1, 2

The International Society for Laboratory Hematology recommends that peripheral blood smear examination is mandatory for MDS diagnosis and serves two critical purposes: evaluation of dysplasia in one or more cell lines and enumeration of blasts 1, 3, 2
The College of American Pathologists recommends counting at least 200 cells on the peripheral blood smear 1, 2
The World Health Organization recommends using May-Grünwald-Giemsa staining for optimal morphologic assessment 1, 2
The American Society for Clinical Pathology recommends that iron staining should also be performed 1, 2

The European Hematology Association recommends that the peripheral smear alone is insufficient for MDS diagnosis—it must be combined with bone marrow examination (aspirate and biopsy), cytogenetic analysis, and clinical correlation 1, 3, 2
When dysplasia is subtle or equivocal, an observation period of 6 months with repeat bone marrow investigation is recommended before confirming MDS diagnosis 3
The National Comprehensive Cancer Network recommends that to qualify as significant in bone marrow, >10% of nucleated cells in the affected lineage must show dysplastic features 1, 2

The American Society of Hematology recommends a complete diagnostic approach that requires bone marrow aspirate and biopsy (mandatory) 1, 3, 2
The International Society for Laboratory Hematology recommends cytogenetic analysis (mandatory for diagnosis and prognostic assessment) 4
The College of American Pathologists recommends flow cytometry immunophenotyping (recommended) 2
The World Health Organization recommends FISH (recommended if standard cytogenetics fail) 3
The European Hematology Association recommends mutation analysis (suggested for prognostic evaluation, particularly TP53 and SF3B1) 5