Basaloid squamous cell carcinoma of the tongue in a Japanese male patient: A case report

Basaloid squamous cell carcinoma (BSCC) is a virulent variant of squamous cell carcinoma. We present a case of BSCC affecting the tongue of a 57-year old Japanese male. Microscopically, BSCC was diagnosed on the basis of presence of basaloid carcinomatous component in intimate contact with smaller areas of conventional squamous cell carcinoma. Immunohistochemistry demonstrated positive staining of tumor epithelium for pan-keratin marker MNF116, CK8, CK17, CK19 and CEA, weak immunoreactivity for CK14, EMA and S-100 protein and negative staining for CK1 and alpha-smooth muscle actin. The principal differential diagnoses considered were adenoid cystic carcinoma, adenosquamous carcinoma and polymorphous low-grade adenocarcinoma.