2 Cases of Intra-Labyrinthine Schwannomas With Different Treatment Options Based on Clinical Presentation

Abstract

Vestibular schwannoma is a benign tumor that arises from the eighth cranial nerve and is the most common neoplasm in the internal auditory canal (IAC). It typically arises in the cerebellopontine angle or in IAC; however, in rare cases, they can arise within the labyrinth. These tumors arising in the labyrinth have been termed intra-labyrinthine schwannomas (ILS) and have different clinical features than the typical vestibular schwannomas. Clinical manifestations of an ILS typically include hearing loss, tinnitus, and vertigo, with unusual symptoms including a sense of fullness or imbalance. Temporal bone MRI is considered the most important test for diagnosing ILS. Tumors show nodular enhancement on T1-weighted images and filling defects on T2-weighted images. Treatment of ILS may include observation, microsurgical resection, and stereotactic radiosurgery depending on the location, size, and clinical presentation. In this paper, we present two cases diagnosed as ILS with different treatment options and provide a literature review for each case.