Solitary S-100-positive congenital granular cell tumor of the tongue: a case report and literature review.

Congenital granular cell tumors (CGCTs), which are rare benign lesions in newborns, locate predominantly on the anterior maxillary alveolar ridge of female neonates. However, this lesion rarely occurs on the tongue, and only 9 cases have been reported in the English literature. Of the 9 cases, which have been tested for S-100 protein, 4 were immunonegative to S-100 protein. In this present case, we reported a rare case of a 4-day-old Chinese girl with a CGCT on the anterior dorsum of the tongue. The lesion was excised under general anesthesia when the newborn was 3 months old. Histologically, pseudoepitheliomatous hyperplasia of the overlying mucosa was noted in this lesion. Immunohistochemical stains showed that the granular cells were diffusely strongly positive to S-100 protein, neuron-specific enolase, and vimentin. Depending on these findings, it was diagnosed as CGCT.