Adenoid basal carcinoma of the uterine cervix: a case report with an immunohistochemical and ultrastructural study.

A case of adenoid basal carcinoma (ABC) of the uterine cervix is reported. The patient was an 80-year-old woman who underwent hysterectomy for uterine prolapse, and ABC was incidentally found in the cervix. The tumor consisted of many cell nests of various sizes, which were composed of small basaloid cells and showed extensive invasion in the cervical wall. Both squamous and glandular differentiations were found in the center of some cell nests. Tumor cells showed the nuclear immunoreactivity for p40 and p63, and the diffuse cytoplasmic immunoreactivity for cytokeratin and p16. Although the deposition of hyaline material was not apparent around cell nests, the cell nests were surrounded by thin, membranous material immunoreactive for laminin, and the ultrastructural study demonstrated an accumulation of electron-dense lamellar material, which formed undulating or loop-forming, "seaweed-like" protrusions on the cell surface. These findings indicate that ABC produces redundant basal lamina material, although its amount is far less than that seen in adenoid cystic carcinoma, another neoplasm of the uterine cervix showing basaloid features.