Embryonal brain tumor with unknown primary lesion and massive cerebrospinal fluid dissemination: A case report

• Published in: Journal of clinical neuroscience Vol. 54; pp. 125 - 128
• Main Authors: Tanaka, Hirotomo, Yamamoto, Daisuke, Ikeda, Mitsuru, Morikawa, Masashi, Ueda, Kayo, Tanaka, Kazuhiro, Sasayama, Takashi, Kohmura, Eiji
• Format: Journal Article
• Language: English
• Published: Scotland Elsevier Ltd 01.08.2018
• Subjects: Biomarkers, Tumor - analysis; Cerebellar Neoplasms - cerebrospinal fluid; Cerebellar Neoplasms - diagnosis; Cerebellar Neoplasms - pathology; CNS PNET; CSF dissemination; Humans; Magnetic Resonance Imaging; Male; Medulloblastoma; Medulloblastoma - cerebrospinal fluid; Medulloblastoma - diagnosis; Medulloblastoma - pathology; Meningeal Carcinomatosis - etiology; Meningeal Carcinomatosis - pathology; Neoplasms, Unknown Primary - cerebrospinal fluid; Pathologic diagnosis; Receptors, Atrial Natriuretic Factor - analysis; Receptors, Atrial Natriuretic Factor - biosynthesis; WHO classification; Young Adult; Pathologic diagnosis; CNS PNET; WHO classification; Medulloblastoma; CSF dissemination
• ISSN: 0967-5868; 1532-2653; 1532-2653
• DOI: 10.1016/j.jocn.2018.04.046

•Recently, embryonal brain tumors of the central nervous system (CNS) were newly codified in the World Health Organization classification up-date in 2016 (WHO 2016).•In WHO 2016, embryonal tumors of the CNS are broadly divided into ‘‘medulloblastoma’’ and ‘‘other embryonal tumors’’, and ‘‘CNS primitive neuroectodermal tumor’’ was removed from the diagnostic list.•The pathologic diagnosis for embryonal brain tumor is sometimes difficult when the tumor location is mostly limited to the cerebrospinal space and the primary lesion can not be determined. The 2007 World Health Organization Classification of Tumors of the Central Nervous System (CNS) categorized embryonal tumors of the CNS into three classes: medulloblastoma, CNS primitive neuroectodermal tumor, and atypical teratoid/rhabdoid tumor. Due to the lack of specific histological features, it was sometimes difficult to accurately differentiate CNS embryonal tumors pathologically. Here, we report a case of a young man, who presented with headache. Gadolinium-enhanced magnetic resonance imaging demonstrated massive lesions in the cerebrospinal fluid space, which strongly suggested leptomeningeal dissemination of a brain tumor. The histology showed the tumor comprised densely packed, small cells with scant cytoplasm. Immunoreactivities were positive for synaptophysin and chromogranin A, and negative for glial fibrillary acidic protein, S-100, EMA, and CD20. Because the tumors were located in multiple sites and most of them were within the cerebrospinal fluid space, the primary lesion could not be determined. We diagnosed this case as ‘CNS primitive neuroectodermal tumor’ by the patient age and predominantly supratentorial distribution of the lesions. After the induction therapy, WHO published its updated classification in 2016. Considering the possibility that the diagnosis is medulloblastoma, we performed additional immunohistochemical analyses, and diagnosed Group 3 medulloblastoma because of the expression of natriuretic peptide receptor 3.