Glossopharyngeal schwannoma causing vocal fold paralysis.

Vocal fold paralysis may occur for a wide range of reasons, from cardiac chamber enlargement, intoxication by chemical products, and mediastinal, neck, lung and intracranial tumors. Given the vast array of possibilities and the various points where the vagus and recurrent laryngeal nerves (the latter is a branch of the first and innervates most laryngeal intrinsic muscles) may be injured, often times complementary tests are required to reach a diagnosis. The glossopharyngeal nerve is both a sensitive and motor entity that emerges from the posterior lateral sulcus of the bulb and exits the skull through the jugular foramen. Similarly, the vagus nerve and the cranial root of the accessory nerve emerge from the posterior lateral sulcus of the bulb and exit the skull through the jugular foramen. The hypoglossal nerve emerges from the anterior lateral sulcus of the bulb and exits the skull through the hypoglossal canal. Therefore, expansive lesions affecting any of these nerves may involve the adjacent cranial nerves by compression. Intracranial schwannomas account for 5-10% of all intracranial tumors. Two to four percent of them are jugular foramen schwannomas. Patients usually present two involved cranial nerves, and symptoms do not help much in identifying the nerve of origin. Collet-Sicard syndrome is a rare manifestation that consists of deficits in the four lower cranial nerves, namely the glossopharyngeal, vagus, accessory, and hypoglossal.