Diagnosing myelodysplastic/myeloproliferative neoplasms: laboratory testing strategies to exclude other disorders.
BACKGROUND
The 2008 World Health Organization classification of myeloid neoplasms includes the diagnostic category, myelodysplastic/myeloproliferative neoplasms (MDS/MPN), which encompasses those rare clonal myeloid proliferations that at initial presentation, show overlapping myeloproliferative and myelodysplastic features, making classification as either a myelodysplastic syndrome (MDS) or myeloproliferative neoplasm (MPN) problematic. There are four main subcategories, chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia, BCR-ABL1-negative (aCML), juvenile myelomonocytic leukemia (JMML), and myelodysplastic/myeloproliferative neoplasm, unclassifiable (MDS/MPN-U), which also includes the provisional entity, refractory anemia with ring sideroblasts associated with marked thrombocytosis (RARS-T). Notably, the morphological features typical of MDS/MPNs are not specific and can be seen in other myeloid neoplasms at presentation or as part of disease progression or transformation.


RESULTS
This review presents a laboratory approach to diagnosing MDS/MPNs in adults that allows for the exclusion of other disorders that may be otherwise indistinguishable. Ancillary studies including cytochemistry, immunohistochemistry, flow cytometry, and genetic testing are discussed.


CONCLUSIONS
The most appropriate classification of myeloid neoplasms presenting with hybrid myelodysplastic/myeloproliferative features requires a comprehensive clinical and laboratory assessment with careful integration of the morphological, immunophenotypic, genetic, and clinical characteristics.
Hall
J
J
Department of Pathology, University of New Mexico, Albuquerque, NM 87102, USA. kfoucar@salud.unm.edu
Foucar
Kathryn
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000754:Anemia, Refractory, with Excess of Blasts / Q000175:diagnosis; D001853:Bone Marrow / Q000473:pathology; D003937:Diagnosis, Differential; D004912:Erythrocytes / Q000473:pathology; D005260:Female; D005434:Flow Cytometry; D006098:Granulocytes / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007951:Leukemia, Myeloid / Q000175:diagnosis; D054438:Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / Q000175:diagnosis; D015477:Leukemia, Myelomonocytic, Chronic / Q000175:diagnosis; D054429:Leukemia, Myelomonocytic, Juvenile / Q000175:diagnosis; D008297:Male; D008533:Megakaryocytes / Q000473:pathology; D009190:Myelodysplastic Syndromes / Q000175:diagnosis* / Q000235:genetics; D009196:Myeloproliferative Disorders / Q000175:diagnosis* / Q000235:genetics; D009504:Neutrophils / Q000473:pathology; D016315:Proto-Oncogene Proteins c-abl / Q000032:analysis; D051562:Proto-Oncogene Proteins c-bcr / Q000032:analysis; D013922:Thrombocytosis / Q000175:diagnosis
D016315:Proto-Oncogene Proteins c-abl; D051562:Proto-Oncogene Proteins c-bcr