Essential thrombocythaemia with aggressive megakaryocytosis after myelofibrotic transformation. Issue 1 (1st January 2021)

• Record Type: Journal Article
• Authors: Sasaki, Ko; Nannya, Yasuhito; Nakamura, Yuko; Ichikawa, Motoshi; Ogawa, Seishi; Mitani, Kinuko
• Is Part Of: Hematology. Volume 26:Issue 1(2021)
• Page Start: 594
• Page End: 600
• Publication Date: 2021-01-01
• Subjects: Essential thrombocythaemia (ET) -- prefibrotic/early stage primary myelofibrosis (PMF) -- post-essential thrombocythaemia myelofibrosis (post-ET MF) -- JAK2 V617F -- U2AF1 S34Y; Blood -- Diseases -- Periodicals; Hematology -- Periodicals; Blood -- Transfusion -- Periodicals; 616.15005
• DOI: 10.1080/16078454.2021.1965714
• Languages: English
• ISSNs: 1024-5332

Abstract

ABSTRACT: Background: Among myeloproliferative neoplasms, it is often difficult to distinguish essential thrombocythaemia (ET) from prefibrotic-stage primary myelofibrosis (PMF) with thrombocytosis given their overlapping clinicopathological phenotypes. Case presentation: We encountered a 45-year-old male who was initially diagnosed with ET and eventually became transformed to secondary myelofibrosis 20 years later. Two distinct types of aberrant megakaryocytes were observed at diagnosis: one type characteristic of ET and the other type characteristic of PMF. With a proliferation in the bone marrow, aberrant megakaryocytes were infiltrated into the extramedullary organs and were even present in the thrombus were observed at autopsy. As a result of next-generation sequencing, the significant increase of variant allele frequency (VAF) of JAK2 V617F and U2AF1 S34Y mutations was observed in the bone marrow cells at the final stage. Conclusions: This patient could be recognized as an atypical case of aggressive megakaryocytosis transformed from ET.