A clinicopathologic study on basaloid squamous cell carcinoma in the oral and maxillofacial region.

Basaloid squamous cell carcinoma (BSCC) is a rare distinct variant of squamous cell carcinoma (SCC). To investigate its clinical behavior and prognosis, 15 patients with BSCC in the oral and maxillofacial region were clinically analyzed and compared with 15 patients with conventional SCC matched for site, stage, gender and age. To understand its immunohistochemical features, sections for cytokeratin AE1/AE3, CK 13. CK 7, CK 8, proliferating cell nuclear antigen (PCNA) and p53 were reviewed from 12 patients with BSCC. The rate of cervical lymph node metastasis of BSCC was as high as 67% and that of distant metastasis 13%. The tumor recurrence rate was 33% and the 3-year and 5-year survival rates were 53% and 32%, respectively. For conventional SCC, the cervical lymph node metastasis rate was 27%, that of distant metastasis 7%, tumor recurrence rate was 33%, and 3-year and 5-year survival rates were 80% and 70%, respectively. In most BSCC patients (10/12) the PCNA index was over 50%. Twelve BSCC patients were diagnosed with grade II or III conventional SCC when the original records of the primary diagnosis for the 15 patients with BSCC were reviewed. The biological behavior and prognosis of BSCC are similar to those of poorly differentiated SCC.