Intracanalicular vestibular schwannomas presenting with facial nerve paralysis

To describe the surgical management and postoperative course of two patients presenting with facial nerve (FN) paralysis as one of the presenting symptoms of small intracanalicular vestibular schwannomas (VS).

Among 153 patients operated for VS since September 2010 to August 2017, two adult female patients presented with rapidly progressive hearing decrease, vestibular symptoms, and FN paralysis (House-Brackmann grades III and IV, respectively). In both cases, c.e. T1-weighted magnetic resonance imaging revealed an enhancing tumor within the internal auditory canal without lateral extension beyond the fundus.

Retrosigmoid approach and excision of tumor showed that the origin of tumor was from the superior vestibular nerve, extrinsic to FN. Gross total tumor resection was obtained, with FN preservation. In the first case, a millimetric fragment of capsule was left because of tight adhesion on FN itself. Histopathology confirmed schwannoma. After surgery, both patients improved FN motor function.

Although very rarely, VS may start clinically with FN palsy, mimicking FN schwannomas and other less common pathologies. This presentation is exceptional in patients with small intracanalicular VS. Early surgical resection is the only reliable treatment for decompression of nerve, avoiding a complete and not-reversible damage, with possible postoperative FN function improvement or complete recovery.