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Bone Marrow
Published in Wojciech Gorczyca, Atlas of Differential Diagnosis in Neoplastic Hematopathology, 2014
Evaluation of megakaryocytes gives important clues in the diagnosis of thrombocytosis, thrombocytopenia, myeloproliferative disorders, and MDSs. It is recommended that at least 20–30 megakaryocytes be analyzed. Normal megakaryocytes are large and have several lobes (Figure 2.7A). Hypolobated micromegakaryocytes may be found in chronic myeloid leukemia (CML; Figure 2.7B) or the variant of MDS (5q− syndrome; Figure 2.7C). In CML, megakaryocytes are dispersed in the background composed predominantly of myeloid precursors with leftward shift, eosinophilia, and basophilia, whereas erythroid precursors are often more abundant in 5q− syndrome (and other types of MDS). The presence of overtly atypical megakaryocytes is seen in non-CML chronic myeloproliferative neoplasms (MPNs) (Figure 2.7D) or myelodysplasia (Figure 2.7E). Chronic MPNs often show increased megakaryocytes with clustering, best appreciated within spicules. Acute megakaryoblastic leukemia (Figure 2.7F) is characterized by the presence of immature megakaryocytes, which display a wide cytomorphologic spectrum, from more mature forms to immature blasts indistinguishable (morphologically) from other types of acute myeloid leukemia (AML). Megakaryocytes are not to be confused with other large multinucleated (multilobated) cells, including atypical multinucleated plasma cells (Figure 2.7G), Reed–Sternberg cells (Figure 2.7H), extrinsic cells (metastatic tumors; Figure 2.7I), histiocytes (including multinucleated cells in infectious/inflammatory processes or hemophagocytic syndrome), and osteoclasts with well-separated nuclei (Figure 2.7J).
Transient abnormal myelopoiesis in Down syndrome: Experience of long term follow up from a single tertiary center in Thailand
Published in Pediatric Hematology and Oncology, 2023
Thirachit Chotsampancharoen, Shevachut Chavananon, Pornpun Sripornsawan, Natsaruth Songthawee, Edward B. McNeil
In our setting, the incidence of TAM associated with DS was 3.2%, which was lower than reported in other studies of 3.8-10%.17,18 The lower incidence in our study may reflect the fact that some DS patients who had an abnormal CBC but no peripheral blood blasts were not included. Further studies should be considered which include DS with abnormal CBC and investigations for GATA1 mutation. Our TAM patients had an overall survival of 87.5%, which is comparable with the results of other studies from Asian and Western countries where rates varied from 63% to 92%.3–5,7 After follow up, the disease spontaneously resolved in 87.5% of our patients as indicated by normalized blood count and absence of circulating blast cells. Massey et al. reported that 89% of their TAM patients spontaneously cleared their peripheral blasts and 64% maintained complete remission. Subsequent acute leukemia developed after TAM, which reported in other studies to be 16-23% at median ages of 1.2-1.7 years.3–5,7 Pine et al., in a study with 585 DS infants, found that 22 (3.7%) had GATA1 mutations and only 2 of these patients (9.1%) subsequently developed acute megakaryoblastic leukemia at 11 and 17 months of age.1 Our research was limited by the lack of a GATA1 mutant study. The median follow up duration of our study was 9.7 years, which was longer than reported in other studies of 1.9-3.5 years.3,4,19,20
Malignancy-associated hemophagocytic lymphohistiocytosis in children: a 10-year experience of a single pediatric hematology center
Published in Hematology, 2020
Zhizhuo Huang, Yueping Jia, Yingxi Zuo, Jun Wu, Aidong Lu, Leping Zhang
Twenty-seven children with M-HLH accounting for 44.3% (27/61) of all types HLH in our study, including 14 male and 13 female (male-to-female ratio, 1.08:1), with a median age of 7 years (range, 0.9–16 years). The median time of diagnosis was 21 days (range, 4–2920 days). Of those, 6 patients (22%) had myeloid malignancy, including acute myeloid leukemia (AML) and MDS, while18 patients (67%) had lymphoid malignancy, including acute lymphoblastic leukemia (ALL), lymphoma and EBV-associated lymphoproliferative disorders (EBV + LPD) and 3 patients (11%) had unknown hematological malignancy. Details are listed in Table 1. There were two patients (No. 2&15) diagnosed with acute megakaryoblastic leukemia (AML-M7) after the first relapse of HLH. After the chromosome analysis, three patients with AML-M7 were proved not having Down syndrome. Only one patient (No. 20) with B-ALL in remission developed HLH, triggered by systemic disseminated mixed infection (may be Candida albicans and tubercle bacilli). Other patients occurred M-HLH simultaneously along with their malignancy development.
Molecular features, prognosis, and novel treatment options for pediatric acute megakaryoblastic leukemia
Published in Expert Review of Hematology, 2019
Federico De Marchi, Marito Araki, Norio Komatsu
Acute megakaryoblastic leukemia (AMegL) is a hematological neoplasm characterized by clonal proliferation of primitive megakaryocytes. First described in 1931 [1], it was included in the FAB classification as acute myeloid leukemia (AML) M7 after defining precise diagnostic criteria; subsequently, AMegL was included in the WHO 2008 classification of myeloid neoplasms [2]. In the most recent 2016 WHO revision of myeloid neoplasms, AMegL is included in Acute Myeloid Leukemia Not Otherwise Specified (AML NOS) [2] and defined as ≥20% blasts in bone marrow cellularity, of which ≥50% are of the megakaryocyte lineage [3].