Mucinous epithelial lesions in endometrial curettage material: a diagnostic challenge.

Aim: To evaluate the immunohistochemical expression of several benign or malignant mucinous lesions that can be encountered in endometrial curettage material.

Materials And Methods: Nineteen well-differentiated mucinous endometrial carcinomas, 12 papillary mucinous metaplasias, 11 cervical microglandular hyperplasias, 11 endocervical adenocarcinomas, 2 goblet cell metaplasias, 1 minimal-deviation adenocarcinoma, and 1 lobular endocervical glandular hyperplasia entered the study. Immunohistochemistry was performed with the following antibodies against: estrogen receptors, progesterone receptors, vimentin, p16, p63, carcinoembryonic antigen, and Ki-67.

Results: Immunohistochemistry could easily distinguish endocervical adenocarcinoma of usual type from all other lesions under study. A Vim(-)/p16(-)/p63(high) signature was found to favor a cervical microglandular hyperplasia, whereas both mucinous endometrial carcinoma and mucinous papillary metaplasia would be preferentially characterized by a Vim(+)/p16(+)/p63(low) immunophenotype. A high Ki-67 expression would be of help in differentiating the latter 2 conditions. Statistically, the expression of estrogen receptors, progesterone receptors, and carcinoembryonic antigen did not aid in the differential diagnosis of these 3 conditions. For the 4 cases representing goblet cell metaplasia, minimal-deviation adenocarcinoma and lobular endocervical glandular hyperplasia, no results could be drawn.

Conclusions: In endometrial curettage material, the differential diagnosis of lesions comprising mucinous epithelium might be rendered by combining the immunohistochemical expression of vimentin, p16, p63, and Ki-67. Of all lesions, endocervical adenocarcinoma of usual type is the most easily identified.