1986 Volume 32 Issue 4 Pages 489-494
In the diagnosis of the small acoustic tumor (AT), ABR and CT scan have recently been the most usefull method. We evaluated an intracanalicular acoustic tumor using ABR and Air CT cisternography. A 49-year-old woman had a sudden episode of vertigo and sensation of unsteadiness. She did not complain of hearing problem and her audiogram was normal. On ABR testing, I-V inter-peak latency (IPL) was prolonged (5.04 msec), and I-V IPL difference was abnormal (1.20 msec). A CT demonstrated a slightly widened left internal auditory canal, but no enhanced mass. ABR testing was repeated using ipsilateral and contralateral recording, and reaffirmed that the I-V IPL was prolonged. We diagnosed a small size AT. An intracanalicular tumor (5mmφ) was found on Air CT cisternography with target imaging. With the team effort of otologists and neurosurgeons, the tumor was removed, preserving the hearing. Her hearing remained at the preoperative level and the I-V IPL decreased (-0.30 msec).
