Welcome to the twenty fourth part of a series on Hemato-oncology.
Question: Dr. Chiragbhai, thank you for initiating discussion about MDS – Myelodysplastic Syndrome i.e. when to suspect this diagnosis. Now can you tell us to how to confirm MDS?
Answer: Yes, MDS is one of the difficult diseases to diagnose. Once it is suspected based on CBC findings as noted in our last discussion, next step is a Bone Marrow Aspiration and Trephine biopsy, with Cytogenetics. In affording patients, it is preferable to add FISH test, as it is a more sensitive test to detect cytogenetic abnormalities of MDS.
Cytogenetic abnormality is the diagnostic test and has major prognostic significance; however it is abnormal in only about 30% of patients. A sample for cytogenetics (heparin tube – green top) should be collected in a bone marrow examination done for any purpose, to avoid a second procedure for patient in case MDS or leukemia is found to be the diagnosis.
In rest of the patients, morphological changes are enough or highly suggestive of MDS. Patients with florid morphological changes are easy to diagnose e.g. obviously dysplastic erythroid series (megaloblastic, nuclear bridging, nuclear lobulations, multinuclearity, cytoplasmic granules), nuclear cytoplasmic asynchrony in early myeloid series, hyposegmented and/or hypogranular myeloid series, ringed sideroblasts more than 15% (for RARS), dysplastic megakaryocytes (multinucleated, micromegs, large monolobed megs).
Many patients however do not have above noted classical findings. Such patients require clinical correlation with duration and pattern of cytopenias, symptoms, other comorbidities and medicines, and other indirect signs on blood and marrow morphology.
Additional important tests include erythropoietin level before initiating red cell transfusions, iron studies, B12 level, TSH.
Other studies done in some patients include copper and ceruloplasmin levels (as copper deficiency can mimic MDS), flow cytometry to rule out a PNH clone or LGL leukemia, HLA typing if patient is candidate for Stem Cell Transplant, JAK 2 mutation if pt has thrombocytosis. Flow cytometry is still not used routinely for diagnosis of flow cytometry, nor for calculation of blast percentage, in MDS.
FAB classification is still used, but increasingly WHO classification is replacing FAB to classify MDS, as it has better correlation with clinical course and prognosis.
Dr. Chirag A. Shah; M.D. Oncology/Hematology (USA), 98243 12144, 98988 31496
Diplomate American Board of Oncology and Hematology. Ahmedabad. firstname.lastname@example.org Shyam Hem-Onc Clinic. 402 Galaxy, Near Shivranjani, Opp Jhansi ki Rani BRTS, Ahmedabad. www.shyamhemoncclinic.com