title: Medulloblastoma simulating acute myeloid leukemia: case report with a review of "myeloid antigen" expression in nonhematopoietic tissues and tumors.
abstract: Medulloblastoma is a primitive neuroectodermal tumor arising in the posterior fossa usually in the first decade of life. Systemic metastases are infrequent at diagnosis and usually occur after surgical resection or shunt placement. We report a rare case of medulloblastoma in an 18-year-old woman who presented with headache, leukopenia, and anemia. Neurologic examination was normal. Bone marrow evaluation revealed primitive cells morphologically resembling blasts. By flow cytometry, these cells lacked CD45 and expressed CD13/33, CD15, CD34, HLA-DR, and strong CD56. The presence of myeloid antigens and CD34 suggested acute myeloid leukemia; however, the bone marrow core biopsy architecture and tumor cells in cerebrospinal fluid were more compatible with a nonhematopoietic tumor. Further workup revealed a cerebellar mass, and a diagnosis of desmoplastic medulloblastoma was made. To our knowledge, this is the first reported case of a nonhematopoietic small round blue-cell tumor expressing multiple myeloid antigens and CD34 by flow cytometry.
authors.affiliation: Department of Laboratory Medicine, University of California, San Francisco, CA 94143, USA. etzellj@labmed2.ucsf.edu
authors.forename: Joan E
authors.initials: JE
authors.lastname: Etzell
authors.forename: Corinne
authors.initials: C
authors.lastname: Keet
authors.forename: William
authors.initials: W
authors.lastname: McDonald
authors.forename: Anuradha
authors.initials: A
authors.lastname: Banerjee
mesh_terms: D000293:Adolescent; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34 / Q000032:analysis*; D000951:Antigens, Neoplasm / Q000032:analysis*; D019046:Bone Marrow Neoplasms / Q000556:secondary; D001859:Bone Neoplasms / Q000556:secondary; D002528:Cerebellar Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D017809:Fatal Outcome; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D007951:Leukemia, Myeloid / Q000175:diagnosis; D008527:Medulloblastoma / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology / Q000556:secondary
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000951:Antigens, Neoplasm