Chronic eosinophilic leukaemia-not otherwise specified (CEL-NOS) is a myeloproliferative neoplasm associated with an autonomous, clonal proliferation of eosinophilic precursors resulting in persistent eosinophilia.A 50-year-old female presented with easy fatiguability, cough and generalised swelling of the body. Investigations revealed anaemia with leucocytosis (56.150 x 103/ul) and 88% eosinophils (absolute eosinophil count was 49412/ul). Peripheral smear showed abnormal eosinophils exhibiting abnormal granulation and nuclear lobation. Reactive causes were ruled out and a bone marrow aspiration/biopsy revealed mildly hypercellular marrow with increased number of eosinophils and their precursors, 7% blasts along with dysplastic megakaryocyteshypolobated and occasional segmented forms. Molecular studies including chromosomal and gene analysis were done. A combination of the clinical picture, laboratory and molecular studies led us to a diagnosis of CEL-NOS.The causes for eosinophilia are myriad and range from reactive causes like parasitic infestations to neoplasms in which eosinophils are a part of the neoplastic population/ are cytokine-mediated reactive component in the background of another neoplasm.The incidence of CEL-NOS is obscure due to significant overlap with Idiopathic Hypereosinophilic Syndrome (IHES). While CEL-NOS is a myeloproliferative neoplasm and its diagnosis can be made provided evidence of a clonality is present, IHES is a diagnosis of exclusion. It is important to differentiate the two entities as they carry different prognosis and modes of treatment.

Background Thrombotic microangiopathy encompasses a wide range of conditions, of which thrombotic thrombocytopenic purpura being a medical emergency requires prompt intervention, with schistocytes being a reliable morphological indicator of microvascular injury. However, there are conditions other than thrombotic microangiopathic anemia where schistocytes can be seen in large numbers. These nonthrombotic microangiopathic conditions are broadly grouped under cytoskeletal abnormalities, mechanical damage, and thermal injuries. Automated methods in schistocyte evaluation have shown varied reproducibility requiring manual identification. International Council for Standardization in Hematology (ICSH) recommends standardized morphological criteria and quantitative assessment as a percentage after counting at least 1,000 red blood cells in optimal areas of smear to reduce interobserver variability. Objectives The aim of this study was to evaluate and quantitate schistocytes in thrombotic microangiopathic and nonthrombotic microangiopathic groups using ICSH guidelines and to evaluate interobserver reproducibility of manual schistocyte count. Materials and Methods Overall, 157 peripheral blood smears showing schistocytes were studied by two independent observers using ICSH recommendations on light microscopy. The hematological findings were correlated with clinical diagnosis and other relevant investigations. Results Schistocytes were observed in five cases of thrombotic microangiopathic anemia and 152 cases of nonthrombotic microangiopathic anemia. Schistocyte count in thrombotic microangiopathic anemia and nonthrombotic microangiopathic anemia groups with mean (±standard deviation) value was 2.28 ± 2.65% and 0.76 ± 0.67%, respectively (p < 0.001). The correlation coefficient between the two observers was 0.59 (confidence interval = 0.966–1.346) showing an excellent agreement on the reproducibility of schistocytes by application of ICSH guidelines. Conclusion Percentage of schistocytes more than 1% is a robust morphological indicator for diagnosis of thrombotic microangiopathic anemia in adults. Strict application of ICSH guidelines reduces interobserver bias.