Differential diagnosis of non-molar gestational trophoblastic neoplasia with ectopic pregnancy by clinical-pathological features.

Purpose: This study was presented to investigate the clinical-pathological characteristics of gestational trophoblastic neoplasia (GTN) following non-molar pregnancy and differentiated with ectopic pregnancy (EP).

Methods: The clinical data of 83 patients who were admitted for suspected GTN after non-molar pregnancy at the Women's Hospital School of Medicine Zhejiang University from January 2015 to September 2022 were selected for analysis.

Results: In total, 41 cases were confirmed non-molar GTN, including 31 choriocarcinoma, 9 PSTT (placental site trophoblastic tumor), and 1 ETT (epithelioid trophoblastic tumor), while 42 cases were confirmed EP. Compared with ectopic pregnancy, non-molar GTN patients had lower levels of serum progesterone compared with EP (3.81 nmol/L vs 17.70 nmol/L, P = 0.001). Based on the ultrasound, the thickness of the endometrium was thinner in patients with non-molar GTN compared with EP (0.565 cm vs 0.70 cm, P = 0.018). By histopathologic examination, the endothelium of non-molar GTN showed less decidual-like changes compared with EP (64.3% vs 14.6%, P = 0.001).

Conclusion: A combination of serum progesterone levels, endometrium thickness, and histopathologic features of the endometrium can help to differentiate non-molar GTN and EP. Surgeries including hysteroscopy with curettage and/or laparoscopy are needed.