Introduction/Background Choriocarcinoma, a rare malignancy, can be gestational or non-gestational. Gestational choriocarcinoma typically affects reproductive-age women post-gestational events, while non-gestational choriocarcinoma primarily involves the ovary and may contain mixed germinogenic components. Regardless of origin, choriocarcinomas elevate human chorionic gonadotropin (hCG) levels in patients. Here, we present a case of endometrial clear cell carcinoma with choriocarcinomatous differentiation.

Methodology Patient C., 54 years old, presented with postmenopausal bleeding and had a history of ectopic pregnancy and ovarian cysts. The patient underwent diagnostic curettage, which suggested undifferentiated polymorphocellular carcinoma with focal choriocarcinoma features. Further examinations included pelvic ultrasound, brain MRI, and PET/CT scans.

Results Ultrasound revealed a 78x37 mm tumor occupying the entire uterine cavity, extending into the cervix, with irregular internal structure and active blood flow. Brain MRI indicated post-stroke changes in the right parietal lobe. PET/CT identified a massive, heterogeneous uterine and cervical tumor measuring 61x96x49 mm, with SUV max up to 5.8. The pretreatment hCG level was 1018 mIU/ml. The patient underwent total hysterectomy, pelvic lymph node dissection, and omentectomy. Microscopic examination revealed two tumor components: adenocarcinoma and pleomorphic cells in necrotic areas. Pathology confirmed ‘Endometrial cancer: clear cell carcinoma with trophoblastic differentiation,’ with each component representing 50%. Invasion extended beyond half the myometrial thickness, involving the cervix stroma. The serous membrane, lymph nodes, and omentum were unaffected. The final stage was pT2N0M0R0. Eighteen days after surgery, the hCG level decreased up to 18 mIU/ml. Patient scheduled for chemotherapy.

Conclusion Endometrial carcinoma with trophoblastic differentiation is rare and primarily occurs in postmenopausal patients. The trophoblastic component is often a choriocarcinoma, while the somatic component varies. Elevated hCG levels are valuable for disease monitoring. The sensitivity to combined chemotherapy regimens remains uncertain due to the limited number of reported cases, necessitating further research.

Disclosures The authors do not disclose any information.