The authors reviewed 102 documented cases of benign extramedullary tumors of the foramen magnum treated at their institution between 1924 and 1982. There was 78 meningiomas, 23 neurofibromas, and one teratoma. Approximately 40% of the patients had a normal neurological examination upon first evaluation. The most frequent presenting complaints were suboccipital neck pain, dysesthesias, gait disturbances, weakness, and hand clumsiness. The average time from initial symptoms to diagnosis was 2 1/4 years. The most common findings included hyperreflexia, arm or hand weakness, Babinski sign, spastic gait, sensory loss, and 11th cranial nerve involvement. Based on these cases, an attempt is made to distinguish foramen magnum tumors from other disease entities by a grouping of signs and symptoms. There is no clinical finding that is pathognomonic. Metrizamide computerized tomography scanning and Pantopaque myelography have been the radiographic tests most commonly used to evaluate the foramen magnum. Recent experience suggests that nuclear magnetic resonance scanning will be a very useful noninvasive means of evaluating the foramen magnum region.

The majority of cerebellopontine angle tumors are acoustic neurinomas; however, 10% to 15% are meningiomas. Meningiomas are benign lesions that must be removed but may require surgical approaches different from those used for acoustic neurinomas. To determine if meningiomas could be distinguished from acoustic neurinomas clinically, findings in 20 patients who underwent removal of a meningioma were compared to those in 131 patients who had an acoustic neurinoma removed during the same period. We found that in patients with meningiomas the tumors frequently are large at presentation, the otologic symptoms and audiometric findings are less dramatic, and roentgenograms of the skull and tomograms of the petrous apex rarely show erosion of the internal auditory canal. Computerized tomography is the most useful method for differentiating a meningioma from a neurinoma: when a meningioma is present the characteristic finding is a broad-based mass aligned with the petrous ridge, not centered over the internal auditory canal.

Primary intracranial lymphoma usually remains localized to the central nervous system, and aggressive radiotherapy will prolong some patients' remission and perhaps cure them. Although the lesion is usually believed to arise from histiocytes or reticulum cells, at least some of the neoplasms are of B-lymphocyte origin. Provisional diagnosis occasionally may be possible by identifying lymphoma cells in the cerebrospinal fluid by using the cytocentrifuge. The use of computed tomography of the head may decrease the need of arteriography for tumor localization.

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Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.