Brainstem astroblastoma with MN1 translocation

• Published in: Neuropathology Vol. 38; no. 6; pp. 631 - 637
• Main Authors: Shin, Sun Ah, Ahn, Bokyung, Kim, Seung‐Ki, Kang, Hyoung Jin, Nobusawa, Sumihito, Komori, Takashi, Park, Sung‐Hye
• Format: Journal Article
• Language: English
• Published: Melbourne John Wiley & Sons Australia, Ltd 01.12.2018; Wiley Subscription Services, Inc
• Subjects: Adolescents; astroblastoma; Brain stem; Central nervous system; Children; Diagnosis; Fluorescence in situ hybridization; gene rearrangement; Glial fibrillary acidic protein; Glioma; Histopathology; Literature reviews; Meningioma; MN1; Tumors; ultrastructure; MN1; glioma; astroblastoma; gene rearrangement; ultrastructure
• ISSN: 0919-6544; 1440-1789
• DOI: 10.1111/neup.12514

Astroblastoma is a rare glial neoplasm that occurs mostly in the cerebral hemisphere of children, adolescents and young adults. Although astroblastic perivascular pseudorosettes are unique histopathology of this neoplasm, diagnosis is usually challenging. Recently, it was discovered that the meningioma 1 gene (MN1)‐altered pediatric central nervous system high‐grade neuroepithelial tumors are actually astroblastomas. This case report presents a rare brainstem astroblastoma, with an unusual immunoprofile: negative for glial fibrillary acidic protein and oligodendrocyte transcription factor 2, but with a robust expression of pancytokeratin and epithelial membrane antigen. The diagnosis was confirmed based on the detection of MN1 rearrangement in a fluorescence in situ hybridization study, in addition to typical histopathology. Here we discuss the diagnostic pitfalls and unclear grading system along with a literature review.