Colloid carcinoma of the uterine cervix: a case report with respect to immunohistochemical analyses.

Colloid carcinoma, characterized by the presence of a large amount of extracellular mucin that results in the formation of mucous lakes with a relative paucity of neoplastic glandular cells within them, is extremely rare in the uterine cervix. Herein, we report an additional case of colloid carcinoma of the cervix and discuss the immunohistochemical characteristics and histogenesis of this extremely rare tumor. A 47-year-old Japanese female without any history of carcinomas was found to have a bulky mass in the cervix. Biopsy from the cervix revealed adenocarcinoma; subsequently, total hysterectomy was performed. Histopathologic study demonstrated that columnar or cuboidal neoplastic glandular cells forming cribriform or tubular structures floated within the mucous lakes involving almost the entire layer of the cervical wall. Adenocarcinoma in situ (AIS) component was also observed. Immunohistochemically, tumor cells of the colloid carcinoma were positive for cytokeratin 7, MUC5AC, MUC6, and p16 (diffuse), but negative for cytokeratin 20, MUC2, and cdx-2. In addition, human papillomavirus 16 was detected in both colloid carcinoma and AIS components. This is the first reported case of endocervical type colloid carcinoma, and the second documented case of cervical colloid carcinoma with immunohistochemical analyses of mucin. The present case had an endocervical type AIS component, which suggests that AIS may be a precursor lesion of colloid carcinoma. Moreover, this case clearly demonstrates that the occurrence of cervical colloid carcinoma correlates with high-risk human papillomavirus.