[Solitary subependymal giant cell astrocytoma: a forme fruste of tuberous sclerosis complex?]

Subependymal giant cell astrocytoma (SEGA) is usually associated with tuberous sclerosis (TS) and believed to originate from subependymal nodules. We report a rare case of SEGA in a patient lacking symptoms of TS. Radiological findings, including CT and MRI, were characteristic of SEGA, but the preoperative diagnosis was difficult due to the fact that no other features of TS were present. TS has been classically characterized by the clinical presence of Vogt's triad of seizure, facial angiofibroma and mental retardation, however, few cases present with all of these manifestations. In 1998, Roarch et al. proposed new clinical diagnostic criteria for the TS complex based on the clinical and radiographic features of TS. According to these criteria, our case is classified as a "possible" TS complex. There have been previous reports of SEGAs without any obvious features of TS, but it is still controversial as to whether these reports represent a forme fruste of TS. To determine a strict diagnosis of SEGA, additional genetic studies are needed. The possibility of SEGA should be considered whenever an intraventricular tumor near the foramen of Monro is found, regardless of other clinical features of TS.