CEREBELLOPONTINE ANGLE LYMPHOMA - A CASE-REPORT AND REVIEW OF THE LITERATURE

BACKGROUND Although malignant lymphomas of the central nervous system have been reported to be increasing in frequency, cerebellopontine (CP ) angle lymphoma is rare and only 13 cases have been reported previous ly in the literature. CASE PRESENTATION A 63-year-old woman had progre ssive dizziness and nausea for 2 months. Computed tomography scanning and magnetic resonance imaging (MRI) revealed a mass lesion in the lef t CP angle, that was compressing the lateral-dorsal aspect of the pens and the fourth ventricle. This tumor was avascular on angiography. Th e tumor was surgically removed through a left lateral suboccipital ap proach. It was considered to arise from the subarachnoid space of the CP angle cistern. For some reason, the histologic diagnosis was not de finitively made, and therefore radiation therapy was not planned. The tumor recurred within 50 days after the tumor excision. Surgical excis ion of the recurrent tumor was performed again. The histologic diagnos is was B-cell type malignant lymphoma. Radiation therapy was performed . In the 27 months since irradiation, a recurrent tumor has not been d etected on MRI. CONCLUSIONS Although erosion and expansion of the inte rnal auditory canal suggest an acoustic neurinoma, CP angle lymphoma c an, in rare circumstances, erode the internal auditory canal. There ar e three distinct patterns in which malignant lymphomas occupy the CP a ngle: (1) an extra-axial CP angle lymphoma, (2) an intra-axial lymphom a extending to the CP angle, and (3) a leptomeningeal lymphoma present ing as a CP angle lesion. Although malignant lymphomas rarely occupy t he CP angle, it should be considered in the differential diagnosis of CP angle tumors. It is desirable to obtain a frozen section in all CP angle tumors during surgery to identify the tumor, because aggressive removal is not necessary, but radiation therapy should additionally be performed for malignant lymphomas. (C) 1998 by Elsevier Science Inc.