2017 Volume 56 Issue 6 Pages 303-307
Background : Atypical teratoid/rhabdoid tumor (AT/RT) is a rare embryonal neoplasm of the central nervous system, classified into WHO grade Ⅳ, that frequently affects young children. Herein, we report the cerebrospinal fluid (CSF) cytological findings in a case of AT/RT in a case with postoperative development of intradural metastasis at the lower lumbar vertebral level with CSF dissemination.
Case : A 7- year-old boy with AT/RT of the brain stem was treated by surgery and postoperative chemotherapy and radiation. Three years after the surgery, he presented with hydrocephalus of acute onset. Magnetic resonance imaging of the head revealed a tumorous lesion in the lumbar spinal cord. Cytology of the CSF showed atypical round cells with occasional rhabdoid morphology, and immunohistochemistry revealed negative staining of the cells for INI-1 protein. Based on these findings, the patient was diagnosed as having recurrent metastatic AT/RT.
Conclusion : To establish the cytological diagnosis of AT/RT, it is important to demonstrate the absence of INI-1 protein expression by immunocytochemistry, especially when the tumor cells exhibit round cell morphology with rhabdoid cells.
