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.

Sella Turcica Atypical Teratoid/Rhabdoid Tumor Complicated with Lung Metastasis in an Adult Female

“…The name atypical teratoid/rhabdoid tumor (AT/RT) exemplifies the tumors disparate mixtures of rhabdoid, primitive neuroepithelial, mesenchymal, and epithelial components, although the tumors may be composed entirely or partly of rhabdoid cells 1–4. The histologic and immunohistochemical features of this neoplasm have been extensively described 5–10. The polymorphous histology prompts misdiagnosis of AT/RT as primitive neuroectodermal tumor (PNET), medulloblastoma, glioblastoma, choroid plexus carcinoma, or malignant teratoma5,6,11–13 The development of AT/RTs have been associated with a specific genetic alteration, that is, mutations of the INI1/hSNF5 gene located on chromosome 22q11.2 14.…”

Atipical teratoid rhabdoid tumor: case report and review of the literature

“…[23][24][25] Moleküler çalışmalarda ATRT'de 22q11 kromozomu uzun kolu üzerinde-ki SFI/SNF kromatin remodelling kompleksinin üyesi olan rabdoid tümör supressör geninde (INI1/ hSNF5) mutasyon varlığı gösterilmiştir. [26][27][28][29][30] İm-münhistokimyasal olarak INI-1 ile boyanmanın olmaması da anlamlıdır.…”

Histology of Primary Brain Tumors

“…Confirmation by cytogenetics for monosomy 22 may be warranted in such cases. Notably is the absence of desmin [72]. MIB-1 labeling index ranges between 30-50%.…”