Spinal Accessory Nerve Schwannoma in a Pediatric Patient: A Rare Microcystic/Reticular Variant in a Non-syndromic Case

Neoplasms of the craniocervical junction in the pediatric population are rare pathologies that represent a therapeutic challenge. We present the case of a 10-year-old male patient with a two-month history of upper limb weakness and gait disturbance. Magnetic resonance imaging revealed a lesion in the foramen magnum. Microsurgical resection was performed via a far-lateral approach, identifying the origin in the spinal accessory nerve. Although initial histopathology suggested a World Health Organization grade 2 chordoid meningioma, immunohistochemistry confirmed a microcystic/reticular-variant schwannoma. Following complementary treatment with radiotherapy due to the initial histological suspicion of a grade 2 meningioma and the complex ventral location of the lesion, the patient showed complete neurological recovery and absence of residual lesion at nine months, highlighting the importance of immunohistochemical diagnosis in determining therapeutic management and prognosis.