A case of septum pellucidum subependymoma with a subtle imaging appearance simulating a cavum septum pellucidum

摘要

Subependymoma is a rare benign slowly growing tumor which usually appears as a well-defined lobulated entirely intraventricular mass, in the fourth or lateral ventricles. We report a case of subependymoma involving the septum pellucidum in a 28 year old female demonstrating a subtle and unusual radiological appearance. It showed very low attenuation on computed tomography, with very high signal on T2- and low signal on T1 weighted magnetic resonance images, merging with the ventricular wall, without definite focal mass. This appearance made the tumor difficult to differentiate from the cerebrospinal fluid and simulating a cavum septum pellucidum. The patient was treated by craniotomy and gross total resection of the mass. Keywords: subependymoma, septum pellucidum, tumor, MRICASE REPORTA 28 years old female was referred to undergo computed tomography (CT) in our institution for papilledema. She was complaining of reduced vision, associated with intermittent headache and vomiting for the last one year. The non-contrast brain CT showed mild dilatation of the lateral ventricles with no definite focal mass, but a vague abnormality noted in the third ventricle, obscuring the septum pellucidum (Fig 1). From this appearance, a mass lesion was suspected and magnetic resonance imaging (MRI) was advised for further evaluation. The CT did not show any evidence of calcification or hemorrhage in the suspicious region. Open in a separate windowFigure 1 28 year old female with septum pellucidum subependymoma. Plain CT Axial showing subtle abnormality in the region of the septum pellucidum which is not normally visualized (arrows), with mild bilateral lateral ventricular hydrocephalus. The neoplasm has a homogenously low attenuation on CT approaching that of CSF giving such appearance. No evidence of calcifications was noted. Spiral CT scan, axial, 5 mm slice, KVP 1.4, exposure 300.