title: Atypical teratoid/ rhabdoid tumor, an immunohistochemical study of potential diagnostic and prognostic markers.
abstract: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare tumor of the CNS mostly seen in infants and is often associated with a dismal outcome. Despite the heterogeneous morphology and/or immunoprofile, its diagnosis nowadays relies on the negative INI-1/BAF47 nuclear immunostain in tumor cells. We aim to investigate a number of immunohistochemical antibodies as potential diagnostic and prognostic markers. All AT/RT cases in patients younger than 18 years of age were included. Demographics, clinical features and outcome were collected. Immunostains tested included SALL-4, OCT3/4, CD99, FLI-1, cyclin-D1, β-catenin, P53, P16, CDX2 and WT-1. Nineteen cases (10 males) were identified at our center between 2004-2013 with a median age of 24 months. Ten (52.6%) cases were supratentorial. Six (42.9%) cases showed metastasis at time of presentation. Chemotherapy was administered to 10 (62.5%) and radiotherapy to seven (43.8%). The median overall survival was 11 months. A single long-term survival of 104 months was identified. Pathologically, most cases showed an admixture of rhabdoid cells and/or small cells and/or pale cells in variable proportions. Of all tested antibodies, only positivity for FLI-1 was associated with improved survival (P = 0.0012), while positivity for cyclin-D1 showed a trend toward improved survival (P = 0.0547). CDX2 was positive only in the single long-term survival. Interestingly, two cases showed co-expression of CD99 and FLI-1, and some were positive for SALL-4. In conclusion, FLI-1 and cyclin-D1 are potential prognostic markers associated with better outcome. Occasional AT/RT cases might co-express CD99 and FLI-1 as well as SALL-4, a potential diagnostic pitfall with Ewing sarcoma/ primitive neuroectodermal tumors and germ cell tumors, respectively.
authors.affiliation: Departments of Pathology, King Hussein Cancer Center (KHCC), Amman, Jordan.
authors.forename: Maysa
authors.initials: M
authors.lastname: Al-Hussaini
authors.affiliation: Departments of Pathology, King Hussein Cancer Center (KHCC), Amman, Jordan.
authors.forename: Noreen
authors.initials: N
authors.lastname: Dissi
authors.affiliation: Departments of Pathology, King Hussein Cancer Center (KHCC), Amman, Jordan.
authors.forename: Cyrine
authors.initials: C
authors.lastname: Souki
authors.affiliation: Department of Pediatric Oncology, King Hussein Cancer Center (KHCC), Amman, Jordan.
authors.forename: Nisreen
authors.initials: N
authors.lastname: Amayiri
mesh_terms: D014408:Biomarkers, Tumor; D016543:Central Nervous System Neoplasms / Q000473:pathology* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D015192:Infratentorial Neoplasms / Q000473:pathology / Q000601:surgery; D008297:Male; D011379:Prognosis; D018335:Rhabdoid Tumor / Q000473:pathology* / Q000601:surgery; D015173:Supratentorial Neoplasms / Q000473:pathology / Q000601:surgery; D016019:Survival Analysis; D013724:Teratoma / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor
keywords: atypical teratoid /rhabdoid tumor; brain tumors; diagnosis; immunohistochemistry; prognosis