title: Histological and immunohistochemical characterization of AT/RT: a report of 15 cases from India.
abstract: Atypical teratoid rhabdoid tumor (AT/RT) is a highly malignant embryonal CNS tumor, generally unresponsive to any form of therapy, uniformly fatal within 1 year. We report 15 cases of AT/RT diagnosed at our center over a period of 5 years (2003-08). Tumors were located in different sites of the neuraxis, posterior fossa being the most common (n = 10) followed by cerebral lobes (n = 3). There was one each at the supra sellar and cervical spinal regions, respectively. Radiologically most of the tumors were heterodense and enhancing heterogeneously. The tumors exhibited diverse histological profile that included rhabdoid and PNET areas in all cases, mesenchymal and epithelial areas in 73.3% and 53.3% cases, respectively. Necrosis was evident in all cases and one showed calcification. Tumor cells displayed a polyphenotypic immunoprofile. All cases were consistently positive for vimentin and epithelial membrane antigen and were negative for desmin. Variable positivity was seen for other markers. The number of cases positive for these were: CK (53%), SMA (60%), synaptophysin (66%), NFP (33.3%) and GFAP (85%). CK staining was prominent in epithelial areas, while PNET cells labeled prominently with synaptophysin. There was lack of INI1 expression in all cases. Follow-up was available in 46.6% of cases which revealed a uniform poor prognosis.
authors.affiliation: Department of Neuropathology, National Institutes of Mental Health and Neurosciences (NIMHANS), Bangalore, India.
authors.forename: Ishani
authors.initials: I
authors.lastname: Mohapatra
authors.forename: Vani
authors.initials: V
authors.lastname: Santosh
authors.forename: Yasha T
authors.initials: YT
authors.lastname: Chickabasaviah
authors.forename: Anita
authors.initials: A
authors.lastname: Mahadevan
authors.forename: Ashwani
authors.initials: A
authors.lastname: Tandon
authors.forename: Amrita
authors.initials: A
authors.lastname: Ghosh
authors.forename: Balasubramaniam
authors.initials: B
authors.lastname: Chidambaram
authors.forename: Somanna
authors.initials: S
authors.lastname: Sampath
authors.forename: Indira Devi
authors.initials: ID
authors.lastname: Bhagavatula
authors.forename: Bangalore Ashwathnarayana
authors.initials: BA
authors.lastname: Chandramouli
authors.forename: Shastry V R
authors.initials: SV
authors.lastname: Kolluri
authors.forename: Susarla Krishna
authors.initials: SK
authors.lastname: Shankar
mesh_terms: D016543:Central Nervous System Neoplasms / Q000737:chemistry* / Q000276:immunology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D007194:India; D007223:Infant; D008297:Male; D009336:Necrosis; D012189:Retrospective Studies; D018335:Rhabdoid Tumor / Q000737:chemistry* / Q000276:immunology / Q000473:pathology*; D013724:Teratoma / Q000737:chemistry* / Q000276:immunology / Q000473:pathology*