Primary malignant rhabdoid tumor of the spinal dura.

We report a case of an intradural extramedullary malignant rhabdoid tumor (MRT) occurring in a 2-year-old girl. Histologically, immunohistochemically and ultrastructurally, the tumor fulfilled the diagnostic criteria for MRT. Many tumor cells contained typical cytoplasmic eosinophilic hyaline inclusions which were filamentous by electron microscopy. Positive vimentin staining was observed immunohistochemically but epithelial markers were negative. Extrarenal MRT are rare. Ten instances in the central nervous system have been reported. This case is the first intradural MRT of the spinal canal. The differential diagnosis from other tumors of this region is important because the prognosis and therapeutic approaches are greatly different.