Objective Human chorionic gonadotropin (hCG) is a glycoprotein hormone expressed in a variety of tumors and is correlated with advanced stage disease and poor prognosis. This study aimed to determine hCG expression immunohistochemically in endometrial specimens obtained from patients with normal endometrium, endometrial hyperplasia, and endometrial carcinoma, and to determine if there is a correlation between invasiveness and hCG positivity.

Methods The histologic materials and medical records for patients diagnosed with normal endometrium, endometrial hyperplasia with/without atypia, and endometrial carcinoma between September 2017 and September 2020 were retrospectively reviewed. Immunohistochemical staining for hCG was performed and analyzed semi-quantitatively.

Results A total of 96 patients were included: normal endometrium (27.1%) (n=26); endometrial hyperplasia without atypia (25%) (n=24); atypical endometrial hyperplasia (22.9%) (n=22); endometrioid endometrial cancer (25%) (n=24). Median age of the patients was 48 (range 28–81) years. hCG was positive in 8.3% of patients with endometrial hyperplasia without atypia, 18.2% in those with atypical endometrial hyperplasia, and 41.7% in those with endometrial cancer (p<0.001). None of the patients with normal endometrium had a positive hCG. The rate of endometrial cancer was 62.5% in the hCG-positive group and 17.5% in the hCG-negative group.

Conclusion hCG is expressed to a significantly greater degree in patients with atypical endometrial hyperplasia and endometrial carcinoma and it may be potentially used as a marker for these lesions.