Intradural, Extramedullary Tumor — Thoracic Meningioma

Abstract

Meningiomas of the spinal canal have accounted for 22 percent of intrathecal tumors seen in the past twenty years at Walter Reed General Hospital. Characteristically these tumors are located anterolaterally in the intradural space of the upper thoracic region. In our series, the average size of the tumor seen at surgery was 2 x 2 cm. Rarely (6 percent) ; this neoplasm is not attached to the dura but is located in the posterolateral quadrant of the spinal cord and is attached to the pia. This type of tumor is usually covered by a shell—like envelope of spinal cord giving the appearance of an intrinsic tumor. We have seen two patients referred to our hospital for irradiation of spinal cord astrocytomas in whom review of the microscopic slides revealed only “gliosis ” and in whom re—exploration uncovered this latter type of meningioma. Because of the severe consequences of mistreating these neoplasms, a tumor in this location is presented.