Pediatric cervical sympathetic chain schwannoma with Horner syndrome: a rare case presentation.

Schwannomas are rare, benign, slowly growing neurogenic tumors that originate in peripheral, spinal, or cranial nerves other than the optic and olfactory nerves. In the head and neck, these tumors usually arise from the vagus nerve and the cervical sympathetic chain in the parapharyngeal space. Cervical sympathetic chain schwannomas represent a rare subgroup of schwannomas; fewer than 60 cases have been reported in the literature.