Basaloid squamous cell carcinoma occurring in the urinary bladder.

Basaloid squamous cell carcinoma is a recently described, distinct variant of squamous cell carcinoma that arises predominantly in the upper aerodigestive tract. Herein we report a case of basaloid squamous cell carcinoma arising in the urinary bladder. The patient was a 60-year-old woman who experienced intractable urinary tract infections following multiple corrective surgical procedures for incontinence. Biopsies of cystoscopically evident flat lesions were performed, and the patient subsequently underwent a radical cystectomy. Histologically, the lesions consisted of nests of basaloid cells with brisk mitotic activity, areas of squamous differentiation along with areas of squamous metaplasia, and squamous cell carcinoma in situ. These features are similar to those of basaloid squamous cell carcinoma described elsewhere in the body. To our knowledge, this is the first reported case of basaloid squamous cell carcinoma in the urinary bladder.