Objective: The aim of this study was to identify distinguishing characteristics of uncommon lesions of the cerebellopontine angle (CPA) and internal auditory canal (IAC) in order to attain the correct diagnosis and thus formulate an appropriate therapeutic protocol.
Study design: A retrospective chart analysis was performed on all patients with surgically managed lesions of the IAC and CPA referred to neuropathology from January 1985 to April 1996.
Setting: All patients were treated by New York University faculty at a tertiary referral center.
Patients: Among 426 surgical cases identified, 384 patients (90.1%) with acoustic neuromas and 18 patients (4.2%) with meningiomas were excluded. The remaining 24 cases, involving 17 women and seven men with a median age of 34 years, were analyzed.
Intervention: Most patients underwent audiovestibular evaluations, as well as magnetic resonance imaging (MRI) and computed tomographic (CT) scanning, and all patients underwent neurotologic surgery as part of their management protocol.
Main outcome measures: Correlating patient presentation, preoperative imaging, and surgical findings often identified distinguishing characteristics of unusual CPA and IAC lesions.
Results: Unusual lesions identified at the CPA and IAC included: four epidermoids, four lipomas, two facial neuromas, two arachnoid cysts, two choroid plexus papillomas, two metastatic adenocarcinomas, one metastatic neuroblastoma, one ependymoma, one lymphoma, one cholesterol cyst, one angioleiomyoma, one venous hemangioma, one cavernous angioma, and one pontine glioma.
Conclusions: Preoperative tumor differentiation based on the patient history, physical examination, audiovestibular testing, CT, and MRI help the surgeon to formulate an appropriate treatment protocol.