Malignant transformation of Warthin's tumor into squamous cell carcinoma: A case report.

Malignant transformation of Warthin's tumor into squamous cell carcinoma is rare. The present study reported on a case of a 67-year-old male patient diagnosed with this condition. Microscopically, the tumor was mainly composed of squamous cell carcinoma and lymphoid stroma. Furthermore, the squamous cell carcinoma cells were arranged in a solid flake-like, papillary and cystic shape. Local bleeding was observed in the mass and a large number of lymphoid stroma-associated centers were observed between the cancer cells. The expression of cytokeratin (CK)5/6, P40, CK7, CK18, CK8 and MutS protein homolog 2 was detected by immunohistochemistry, in addition to Epstein-Barr encoding region in situ hybridization (-), Ki-67 (epithelial 25% +) and p53 (wild-type). The diagnosis of malignant transformation of Warthin's tumor into squamous cell carcinoma depends on the histopathology. The microscopic diagnosis is based on the dynamic process of scaling, atypical hyperplasia and cancerization of the eosinophilic columnar epithelium. Of note, it is also necessary to differentiate it from cervical malignant tumors such as lymphoepithelial carcinoma. The main clinical treatment is surgical resection with negative margins.