title: Relapse of acute myelogenous leukemia as a cerebellar myeloblastoma showing megakaryoblastic differentiation.
abstract: Myeloblastomas (granulocytic sarcomas) occurring within the central nervous system (CNS) are extremely rare lesions that may develop in patients with acute or chronic myeloproliferative disorders. The majority of such lesions involve brain or spinal cord by contiguous spread from meningeal or bony sites, rather than originating within the CNS parenchyma. We describe a patient with acute myelogenous leukemia in remission, who developed a purely intraparenchymal cerebellar myeloblastoma with megakaryocytic differentiation. The neoplastic cells expressed the megakaryocytic markers factor VIII-related antigen and platelet glycoprotein-IIIa (CD61), and showed ultrastructural features that were indicative of megakaryocytic differentiation. Clinically, myeloblastomas of the CNS invoke a broad differential diagnosis that includes abscess, hemorrhage, and metastatic neoplasms because of their intraparenchymal location and radiologic features. Although they are rare, myeloblastomas should be included in the histopathologic differential diagnosis of a poorly differentiated neoplasm occurring within the CNS, particularly in a patient with a history of myeloproliferative or myelodysplastic disease.
authors.affiliation: Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA. robert.lorsbach@stjude.org
authors.forename: R B
authors.initials: RB
authors.lastname: Lorsbach
authors.forename: R D
authors.initials: RD
authors.lastname: Folkerth
authors.forename: G S
authors.initials: GS
authors.lastname: Pinkus
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D002454:Cell Differentiation; D002528:Cerebellar Neoplasms / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D039661:Integrin beta3; D007947:Leukemia, Megakaryoblastic, Acute / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D007951:Leukemia, Myeloid / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D015470:Leukemia, Myeloid, Acute / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D012008:Recurrence; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D039661:Integrin beta3; D010980:Platelet Membrane Glycoproteins; D014841:von Willebrand Factor