Document Type : Research Articles
Department of Pathology and Laboratory Medicine, Aga Khan University Hospital, Karachi, Pakistan.
Department of Pathology, College of Medicine Alfaisal University, Riyadh, Saudi Arabia.
Background: Atypical teratoid/ rhabdoid tumor (AT/RT) is a rare aggressive embryonal central nervous system
(CNS) tumor of infancy and early childhood. Majority of the cases arise in the posterior fossa, and remaining in the
cerebrum. Aims: To analyze the clinicopathologic features of AT/RT on a cohort of cases. Materials and methods:
All reported cases of AT/RT at the Department of Pathology and Laboratory Medicine, Aga Khan University Hospital
(AKUH) from 2007 to 2016 were reviewed for clinical and pathological features. Immunohistochemical stain for INI-1
was performed in all 11 cases. Follow up was obtained. Results: A total of 11 cases were identified. Seven patients were
males and 4 were females. The ages ranged from 1 month to 48 months (mean 26.6 months). Six tumors were located
in the cerebrum and 3 in the posterior fossa. Exact Location was not known in 2 cases. Histologically, rhabdoid cells
were present in sheets in variable proportions in five cases, Medulloblastoma and PNET like areas were seen in 2 cases
each. Immunohistochemical stains EMA (10/10), vimentin (7/7), CKAE1/AE3 (8/9), and CD99 (3/4), GFAP (6/10),
ASMA (3/4) and synaptophysin (3/4) were positive in varying proportions while desmin was negative in all 6 cases in
which it was performed. All 11 tumors lacked immunoreactivity for INI-1 protein. Four patients died of disease with
a follow up ranging from 5 to 24 months. Conclusions: AT/RT is a rare highly aggressive embryonal tumor of CNS.
A male predominance was noted in our series. We report the first and largest series from Pakistan.