Filum Terminale Schwannoma Presenting as a Purely Cystic Lesion on Non-Contrast Magnetic Resonance Imaging: Case Report

Spinal schwannomas are benign nerve sheath tumors that typically present as solid or heterogeneous, well-circumscribed masses with contrast enhancement on magnetic resonance imaging (MRI). A 61-year-old male presented with progressive low back and leg pain. Non-contrast MRI revealed an apparently completely cystic intradural mass at the level of the conus medullaris. Contrast-enhanced MRI demonstrated heterogeneous enhancement. The lesion was totally excised via laminectomy under intraoperative neuromonitoring and was found to originate from the filum terminale. Histopathological examination confirmed the diagnosis of schwannoma. This case highlights the importance of contrast-enhanced MRI for accurate differential diagnosis of intradural lesions, the role of intraoperative neuromonitoring in preventing neurological deficits, and the necessity of histopathological examination for definitive diagnosis.

Keywords: Cyst; Magnetic resonance imaging; Resection; Schwannoma