MR findings in intralabyrinthine schwannomas

AIM: Intralabyrinthine schwannomas (ILS) are rare benign tumours. They are not always recognized on routine magnetic resonance imaging (MRI). We aimed to study the clinical presentation and MRI findings in our patients with ILS. MATERIALS AND METHODS: Retrospective analysis of patients with vestibular schwannomas treated at this center. RESULTS: Of 144 vestibular schwannomas studied at this centre, three patients had an ILS. The most common presenting symptoms were unilateral hearing loss, tinnitus and vertigo. Two patients demonstrated a progressive sensorineural hearing loss (SNHL). The third patient had a severe SNHL at presentation. MRI enhanced with contrast medium was positive in the two patients with progressive SNHL and negative in the patient with the severe SNHL. CONCLUSION: This series demonstrates the ability of MRI to identify schwannomas filling the labyrinth, and also its inability to identify extremely small ILS. It underlines the importance of sending the cristae of patients undergoing labyrinthectomy for presumed Meniere's disease for histological examination. (C) 2002 The Royal College of Radiologists.