Abstract
The growth rate of the acoustic tumor was measured in 6 cases in which the surgery was deferred with various reasons and the follow up studies were done during the period of the observation. The size of the tumor was less than 12mm in all cases including one case of an ear tumor and the observation period ranged from 4 to 31 months. In one case, the operation was performed 4 months after the diagnosis because of the rapid growth of the tumor but others were still under observation. The growth rate of the tumor determined by CT-Scan was various in each case, ranging from no growth to 21.9mm/year. Excluding the case of no growth, the calculated volume doubling times were 5 years, 8.2 months, 3.2 month (2 cases) and 1.5 months in 5 cases, respectively. Among the various otoneurological examinations, ABR was the most sensitive to the tumor growth. When one must observe the patients of the acoustic tumor without surgery, it is necessary to take into consideration that some of them exhibits the rapid growth.
