Cerebellopontine angle tumors: their roentgenologic manifestations.

Abstract

Two years ago we recorded our findings in 122 patients with proved acoustic nerve tumors operated upon in the Hospital of the University of Pennsylvania, the Graduate Hospital of the University of Pennsylvania, and the Temple University Hospital (5). At that time we concerned ourselves only with eighth nerve tumors. The present report will bring our experiences with acoustic nerve tumors in the Hospitals of the University of Pennsylvania up to date. In addition, we have reviewed the records of all other patients operated upon for cerebellopontine angle tumor syndromes who proved to have neoplasms other than acoustic neuromas. The roentgen findings in these cases, also, will be recorded. The data for this report were taken from the records of the Neurosurgical Services of the Hospital of the University and the Graduate Hospital of the University of Pennsylvania, made available to us through the kindness of the neurosurgeons of these hospitals, Dr. Francis C. Grant and Dr. Robert A. Groff. Our present series comprises 183 patients with angle tumors operated upon in the two hospitals. Of this group, 134 had eighth nerve tumors, 19 had meningiomas, 16 gliomas, 7 cholesteatomas of the cerebellopontineangle, 3 hemangioblastomas, and there were single cases of metastatic carcinoma, encapsulated hemorrhage, chondrosarcoma, and chondromyxoma (Table I). Having reviewed the anatomy of the cerebellopontine angle only two years ago (5), we will not repeat the description, nor will the roentgen anatomy of the petrous pyramid be summarized again. Suffice it to say that petrosal pyramids and internal acoustic meatuses vary remarkably from patient to patient, and, indeed, on both sides of the same individual. Familiarity with these normal variations is of paramount importance if false positive reports are to be avoided. For these valuable observations, the reader is referred to the studies of Ebenius (2) and Camp and Cilley (1) previously reviewed by us in detail. Eighth Nerve Tumors Of the 134 true tumors of the eighth nerve, constituting 73 per cent of our entire series, the vast majority proved to be acoustic neurinomas (93 per cent); the rest were acoustic neurofibromas of the von Recklinghausen type. The reader is referred to our previous report for a detailed account of the pathology of eighth nerve tumors. To revie where briefly: In neurinomas, the nerve fibers are demonstrated only in the capsule of the tumor, while in the neurofibromas of von Recklinghausen the nerve fibers penetrate the tumor. Whereas the former are usually single lesions, von Recklinghausen's tumors often prove to be bilateral and familial. Not infrequently the latter are associated with neurofibromas involving other cranial or peripheral nerves and, in rare instances, with meningiomas. Eighth nerve tumors usually follow a characteristic progressive pattern of neurologic signs and symptoms.