Synchronous lingual granular cell tumor and squamous carcinoma. A case report and review of the literature.

Granular cell tumor (GCT) is a benign lesion with a preference for subcutaneous sites. Marked pseudoepitheliomatous hyperplasia, seen in 10% of GCTs, might be misdiagnosed as squamous cell carcinoma (SCC), and GCT in the oral tissues has been referred to as a medical curiosity in the literature. We report the clinicopathologic, immunohistochemical, and ultrastructural findings in a case of coexistent SCC and GCT in the tongue. There is no evidence in this case that suggests malignant transition of the GCT to carcinoma. To the best of our knowledge, this is the first report of synchronous GCT and SCC in the oral cavity.