[Carcinoma cuniculatum of the oral cavity. A contribution to the differential diagnosis of potentially malignant papillary lesions of mouth mucosa].

Although carcinoma cuniculatum clinically appears to be malignant, histological evaluation often results in a false diagnosis of a benign papillomatous lesion or pseudoepitheliomatous hyperplasia, because the tumor usually displays a well differentiated tissue. In this report morphological and immunohistological features in a rare case of carcinoma cuniculatum of the oral cavity are described. Both clinical features and histomorphological evaluation must be taken into consideration when diagnosing the tumor.