Neurotologic disease in four patients with normal audiometric findings.

Clinical suspicion remains an underlying diagnostic clue in the evaluation of patients with unconfirmed acoustic neuromas. This is particularly true when initial otologic and audiologic evaluations are equivocal. This paper summarizes a series of four patients each who demonstrated normal audiometric (pure-tone and conventional speech audiometry) and/or ABR findings in the presence of surgically confirmed intracanalicular or cerebellopontine angle tumors. Three of the patients presented with evidence of "classical" acoustic tumors, whereas the fourth patient revealed a benign internal auditory canal capillary hemangioma. Audiologic evaluation, ABR measures, and MRI scanning demonstrate the relationships observed in each of the four patients. Diagnostic strategies illustrate the importance of cross-check principles (audiologic, electrophysiologic, and imaging techniques) in the diagnosis of posterior fossa tumors. The presence of normal pure-tone thresholds should not discourage the pursuit of additional diagnostic measures if clinical suspicion remains a factor in comprehensive patient management.