Atypical teratoid/rhabdoid tumor with retained INI1 (SMARCB1) expression and loss of BRG1 (SMARCA4). Issue 3 (21st December 2017)

• Record Type: Journal Article
• Authors: Bookhout, Christine; Bouldin, Thomas W.; Ellison, David W.
• Is Part Of: Neuropathology. Volume 38:Issue 3(2018)
• Page Start: 305
• Page End: 308
• Publication Date: 2017-12-21
• Subjects: atypical teratoid/rhabdoid tumor -- BRG1 -- INI1 -- SMARCA4 -- SMARCB1; Nervous system -- Diseases -- Periodicals; Nervous system -- Pathophysiology -- Periodicals; 616.8047
• DOI: 10.1111/neup.12452
• Languages: English
• ISSNs: 0919-6544

Abstract

Abstract : Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, highly aggressive malignancy of the central nervous system (CNS) usually diagnosed in infancy or childhood, most often characterized by loss of expression of the SMARCB1 gene product integrase interactor 1 (INI1) protein. We report a case of AT/RT in a 3 month old boy with retained expression of INI1 by immunohistochemistry. Additional testing demonstrated loss of expression of the SMARCA4 gene product Brahma‐related gene 1 (BRG1) protein by immunohistochemistry, confirmed by next generation sequencing showing a nonsense mutation in SMARCA4. This case illustrates that positivity for INI1 does not rule out a diagnosis of AT/RT, and additional testing, including BRG1/ SMARCA4 analysis, is warranted in cases where clinical suspicion is high.