Oral and pharyngeal adenosquamous carcinoma. A report of four cases with immunohistochemical studies.

Four cases of adenosquamous carcinoma from the oral and pharyngeal cavities were analyzed by light microscopy and immunohistochemistry. Lymph node metastases were present in three cases. One patient died 2 years after treatment. All four carcinomas presented a mixture of squamous and glandular mucus-secreting neoplastic elements. Immunostaining for high-molecular-weight cytokeratins (KL1) was constantly positive in both squamous and glandular tumor cells. Antibodies against low-molecular-weight cytokeratins (K19) and carcinoembryonic antigen were positive only in the glandular component. The histological aspect and the immunohistochemical phenotype of these tumors is similar to the ordinary squamous cell carcinoma and adenocarcinoma, respectively.