Ancient schwannoma of the oral floor and ventricular portion of the tongue: a case report and review of the literature.

We report a case of ancient schwannoma, which is a rare benign neoplasm of the oral floor and ventricular portion of the tongue. Only two cases have previously been reported in the English literature. The present tumor, measuring 5.5 x 3.0 x 3.0 cm, was the largest of the three. To differentiate ancient schwannoma from schwannoma with malignant transformation, it is important to confirm the absence of abrupt transition between areas of apparently typical schwannoma and areas composed of atypical large cells with pleomorphic and hyperchromatic nuclei, as well as the absence of mitoses, necrosis, and invasiveness. In the present case, calcification was not detected, nor was hyalinization extensive, although many of the neoplastic Schwann cells showed degenerative nuclear atypia.