Giant Bicompartmental Cystic Tentorial Schwannoma Mimicking a Meningioma.

Abstract

Intracranial schwannomas most commonly arise from the vestibulocochlear nerve and less frequently from trigeminal, facial, and hypoglossal nerves. Intracranial schwannomas unrelated to cranial nerves are very rare; only approximately 50 cases have been reported in the literature. Tentorial schwannoma (TS) is even rarer, with only 13 cases reported to date. We present a rare case of giant TS. A 21-year-old man presented with generalized headache and dizziness for the past 6 months and worsening of symptoms for the past 2 months. On evaluation, he was found to have a cystic lesion arising from the right tentorium with multiple internal septa and fluid levels, with both supratentorial and infratentorial extension. The presence of a dural tail sign and tentorial origin led us to make a preoperative diagnosis of tentorial meningioma. The patient underwent complete excision, and a diagnosis of TS was made based on histopathologic analysis. TSs are extremely rare. Knowledge of radiologic and morphologic features can be helpful in making a preoperative diagnosis. The dural tail sign, which is considered a characteristic feature of meningioma, is commonly seen in TS as well, and thus TS should always be considered in the differential diagnosis of lesions arising from the tentorium.