Basaloid squamous carcinoma of the head and neck. Report of a case occurring in the anterior floor of the mouth.

Basaloid squamous carcinoma was initially characterized in 1986, and it has been an uncommon entity, with 86 reported cases occurring in the head and neck. Although histologically associated with squamous cell carcinoma and squamous atypia, basaloid squamous carcinoma has distinctive clinical features. It is frequently diagnosed at an advanced stage, often with distant metastases, and it may be associated with second primary tumors. This tumor most commonly occurs in the base of the tongue, hypopharynx, and larynx. We report a case of basaloid squamous carcinoma that occurred in the anterior floor of the mouth--a distinctly unusual location.