Basaloid squamous carcinoma of the upper aerodigestive tract. Clinicopathologic and DNA flow cytometric analysis

This report adds nine basaloid squamous carcinomas (BSC) of the upper aerodigestive tract to the 11 already recorded in the literature. It includes the first flow cytometric analysis of their DNA content and compares the clinical behavior of BSC with conventional squamous cell carcinoma (SCC). An uncommon variant of squamous carcinoma, BSC manifests a predilection for the hypopharynx and base of tongue of men in the sixth decade of life. Histologically, the carcinoma is characterized by a basaloid pattern often in an intimate association with focal squamous differentiation, comedonecrosis, and stromal hyalinization. It is an aggressive neoplasm: seven of the nine patients had metastases to cervical lymph nodes at time of initial surgery and three of the five deaths occurred within 24 months after primary surgery followed by radiotherapy. Its aggressiveness notwithstanding, the biologic course of BSC is similar to that of conventional SCC when clinical stage, site, and treatment are matched. Patients with aneuploid BSC had a better mean survival time (39.5 months) than those with diploid carcinomas (16.3 months). Surgery followed by radiotherapy appears to be the treatment of choice. Because of a high incidence of distant metastases, adjuvant chemotherapy may be warranted.