一側内耳道拡大を示した3症例の検討

抄録

Case 1 was considered to be an acoustic tumor (AT) on the basis of a marked decrease of caloric response and a broad action potejtial (AP) on ele-ctrocochleography (ECoG) of the left ear, but showed only a C5 dip sensory hearing loss on both sides. Case 2 was considered to be an AT becoase of profound hearing loss and no response of AP with detectable cochleomicrophonics (CM), but the caloric response of the left ear was almost normal. Case 3 was presumably an AT with deafness, no caloric response and no AP response with detectable CM. In all three cases there was enlargement of the JAM on the left side. Air CT cisternography in cases 1 and 2 showed a small AT in the IAM, but no AT was detected in case 3. We conclude that the diag-nosis of early AT cannot be made with certainty without air CT cisternography.