Posterior Fossa Melanocytic Schwannoma Extending to the Cervicothoracic Spinal Cord: A Clinical Rarity

Background: Melanocytic schwannomas (MSs) are rare, malignant peripheral nerve sheath tumors with only 200 cases reported to date. These pose imaging and pathological challenges for definitive diagnosis.

Case Description: A 25-year-old lady presented at our center with a prolonged history of gait disturbance, left ear tinnitus, headaches, and drowsiness. MRI findings showed a midline cystic lesion in the posterior cranial fossa extending caudally to the D1 vertebral body, with marked central hypointensity, and peripheral hyperintensity on T1-weighted images. A suboccipital craniotomy and debulking of the lesion were performed, showing a hyperpigmented, infiltrative tumor adherent to the surrounding structures. This was confirmed as a melanocytic schwannoma on histopathological analysis.

Conclusion: Posterior fossa MSs involving cervicomedullary region and extending distally to cervicothoracic spinal cord are rare and complex cases, particularly with regard to difficulty diagnosing preoperatively and surgical resection.