MAGNETIC-RESONANCE-IMAGING AND INTRAOPERATIVE FROZEN-SECTIONS IN INTRATEMPORAL FACIAL SCHWANNOMAS

Seven cases of intratemporal facial schwannoma were assessed by preope rative magnetic resonance imaging (MRI) and intraoperative frozen sect ions to determine tumor boundaries. These results were then analyzed w ith respect to gross tumor appearance, under the operating microscope, and final histopathologic diagnosis, with immunostains. Gadolinium-en hanced MRI was helpful in planning the surgical approach and in defini ng the extent of tumor involvement relative to the facial nerve. Froze n sections on the other hand were often unreliable in confirming the c ompleteness of resection, frequently overestimating tumor infiltration . Ultimately, tumor-nerve interface, especially in the proximal facial segments, is best judged by its gross intraoperative appearance under high magnification, with the aid of MRI. The difficulty in establishi ng tumor infiltration in the presence of organized neural fibers and a rtifacts is emphasized. Immunohistochemical assays are essential in th is regard. Complete tumor removal was achieved in all seven cases, wit h acceptable functional outcome in those with sufficiently long follow -up.