Schwannomas are characterized by bland palisading cells with slender nuclei. The 2 classic conformations are the Antoni A and Antoni B patterns. Hemangiomas are highly vascular lesions consisting of endothelium-lined channels. Because of the proclivity of hemangiomas to be found near the geniculate ganglion, neuronal cell bodies and bone fragments often accompany the histologic specimen. Surgery is the preferred therapeutic modality for schwannomas and hemangiomas of the facial nerve.
Decision making regarding surgical approach is based on the anatomical location of the tumor.
Timing of surgical intervention presents a thornier dilemma. Hemangiomas, with their proclivity to arise at the geniculate ganglion, often are confined to the middle cranial fossa and therefore can be removed via a subtemporal craniotomy. If the tumor extends laterally down the labyrinthine segment or along the tympanic segment of the facial nerve, a combined approach incorporating a postauricular mastoidectomy may become necessary. Surgical removal of facial nerve schwannomas is approached similarly. These tumors are more likely to extend into the cerebellopontine angle and therefore also may reach a larger size before they become symptomatic.