2026 Poster Presentations
P093: MANAGEMENT AND OUTCOMES OF TRANSOTIC SCHWANNOMA: A 3 CASE SERIES
Sophie Jabban, BA; Michael Bartellas, MD, MSc; J Thomas Roland, MD; David Friedmann, MD, MSc; NYU Grossman School of Medicine
Background: Transotic schwannomas (TOS) are a rare subtype of inner ear schwannoma (IES) defined by their involvement of the internal auditory canal, inner ear, and middle ear spaces. While incidence rates are not well-defined, the incidence of IES is approximately 1 in 100,000, with one study identifying TOS in 2 of 45 IES cases. Management of IES is complex and centers precise tumor location and patient symptomatology. Given this tumor’s rarity and diverse treatment modalities, our study aims to outline the management and outcomes of 3 patients with TOS.
Methods: We performed a single-institution retrospective review and identified three patients diagnosed with TOS between 2013-2025.
Results: Case 1. A 28-year-old presented with progressive ear fullness, vertigo, tinnitus, ipsilateral facial-twitch, and profound sensorineural hearing loss (SNHL). MRI demonstrated an enhancing mass within the right internal auditory canal (IAC) with extension to the cerebellopontine angle (CPA), basal and middle turns of the cochlea, vestibule, proximal semicircular canals (SCC), and middle ear. Microsurgical resection was determined after multidisciplinary review. A transcochlear approach with blind sac closure of the ear canal was performed. Pathology demonstrated Grade I schwannoma with a Ki-67 index of 10%. Postoperatively, the patient had a pseudomeningocele and underwent lumbar drain placement with resolution. They developed delayed post-operative ipsilateral facial weakness for one month with complete resolution.
Case 2.A 59-year-old presented with ipsilateral facial spasms, vertigo, and SNHL. MRI demonstrated an enhancing mass in the right IAC extending to the CPA; cochlea; vestibule; lateral, posterior, and superior SCCs; and middle ear. An initial period of active surveillance was followed by Gamma Knife Radiosurgery (GKR) for tumor growth after five years. Following treatment, they experienced complete resolution of facial twitching, no complications, and no improvement in hearing loss.
Case 3. A 63-year-old presented with tinnitus, vertigo, and SNHL. MRI demonstrated an enhancing mass in the left IAC, extending to the CPA, vestibule, cochlea, and middle ear. After two years of active surveillance, they underwent a left retrosigmoid approach for microsurgical gross total resection. Pathology demonstrated Grade I schwannoma with Ki-67 index of 5%. Schwannoma recurrence was noted two years after initial resection, leading to re-resection at an outside institution. The patient experienced two additional recurrences two and five years later, both managed with GKR. Following each treatment, they experienced House-Brackmann II to III facial paralysis that ultimately improved with facial PT and botox chemodenervation.
Discussion: Decision making regarding surgical and non-surgical approaches in TOS management is complicated and often surgeon and institution dependent. Due to the nature of TOS, considerations regarding access to the middle ear space is important, with petrosal approaches providing direct entry. Surgical approach may also influence outcomes, with studies demonstrating higher rates of recurrence and facial nerve damage with the retrosigmoid approach. At times, as noted in Case 1., evolving to the more technically demanding transcochlear approach may be necessary. This series implies the importance of tailoring management to precise tumor location and detailed pre-operative planning, with multidisciplinary review in TOS management.