Purely Endoscopic Retrosigmoid Approach for Excision of a Large Multicystic Hypoglossal Schwannoma

Abstract

Hypoglossal schwannomas are rare tumors that account for 1%-7% of all nonvestibular intracranial schwannomas. They commonly affect middle-aged females.1 They can be completely intracranial (type A), intracranial/extracranial (type B), or completely extracranial (type C).2 Presenting symptoms include hypoglossal nerve dysfunction, additional lower cranial neuropathies and, rarely, increased intracranial pressure. Patients with the rare extracranial tumors most commonly present with an asymptomatic mass in the neck or submandibular region.3 Treatment options include observation in small asymptomatic tumors and surgical excision in large tumors with mass effect. In tumors that require treatment and are within the size range, radiosurgery should be considered.1 In this operative Video 1, the patient is a 45-year-old woman who presented with a 1-year history of progressive headaches, right-sided retroauricular pain, unsteady gait, hoarseness of voice, and dysphagia. Neurologic examination revealed right cranial nerves IX to XII palsies, pyramidal manifestations, and right cerebellar ataxia. Imaging findings were consistent with large multicystic hypoglossal schwannoma. A purely endoscopic retrosigmoid approach was performed for excision of the lesion. A 4K rigid endoscope offers a highly illuminated and extremely detailed views of the tumor and the anatomic structures within the surgical field, adding greatly to the safety of surgery. Furthermore, the panoramic view and large depth of focus of the endoscope result in greater ease of orientation within the surgical field with significant reduction of the number of times the viewing angle needs to be changed during the procedure.