Acoustic neurilemmoma

Abstract

✓ Clinical data in 103 patients with acoustic neurilemmoma were correlated with anatomical findings. The tumors were more common in women. Peak prevalence was in the fifth and sixth decade without difference between the sexes. The neoplasms were divided into four sizes: small, medium, large, and giant. Small (intracanalicular) tumors occurred more often in men, were of equal frequency in the decades from 20 to 70 years, were generally associated with long duration of illness, were highly cellular, and had few blood vessels. They, therefore, differed from extracanalicular neurilemmomas, and are better considered as “minimal” rather than “early” tumors. Large and giant lesions occurred more often in women, were more heavily vascularized and collagenized, were more liable to bleed, contained fewer cells, and were often associated with symptoms of short duration. The length of illness ranged from 1 month with a 6-cm lesion, to 30 years with a 1-cm mass. It is suggested that although most tumors enlarge slowly, the rate of growth may vary widely. The unilateral acoustic neurilemmoma that rarely occurs in the first two decades of life may be a limited form of von Reckinghausen's disease. Mortality in this series was nil, and hence was unrelated to size of tumor as described in earlier reports. Angiomas were found in 24 schwannomas, and microscopic calcification in four. Vascular spaces resembling cysts often were formed by tumor cells. The histological development of acoustic neurilemmoma is hypothetically reconstructed.