Objectives It is clinically important to determine whether adenocarcinoma present in a biopsy or curettage is of endometrial or endocervical origin. When tumors are difficult to distinguish based on routine histologic sections, immunohistochemistry and human papillomavirus (HPV) in situ hybridization may be used.

Materials and Methods We compare immunohistochemical profile and HPV expression in 76 tumors, including various types of endocervical adenocarcinoma and the most common endometrioid type of endometrial adenocarcinoma using tumor tissue microarray. Immunostaining for p16, mammaglobin, vimentin, monoclonal carcinoembryonic antigen, estrogen receptor, progesterone receptor, and PAX-8 as well as HPV in situ hybridization was performed in 37 endocervical adenocarcinomas and 39 endometrioid-type endometrial adenocarcinomas. The staining patterns were analyzed with Bayesian network model.

Results The markers with the highest discriminatory values were p16, HPV, vimentin, estrogen receptor, and monoclonal carcinoembryonic antigen. The various histologic types of endocervical adenocarcinoma showed similar immunohistochemical profile, and most were positive for p16 (86%) and HPV (65%). Most (90%) of the endometrial adenocarcinomas were positive for vimentin and estrogen receptor, all were negative for HPV, and 97% were negative for carcinoembryonic antigen.

Conclusions Immunohistochemical testing with multiple markers and HPV testing aids in diagnostic evaluation of adenocarcinomas of endocervix and endometrium and is recommended in tumors of uncertain origin.