Characteristics of Epithelioid Trophoblastic Tumor: Endoscopic and Magnetic Resonance Imaging Findings

Epithelioid endothelial tumor (ETT) is an extremely rare tumor that typically occurs in women of reproductive age. The diagnosis tends to be delayed because it often necessitates a total hysterectomy. Therefore, it is important to understand ETT macroscopic and imaging findings. Here, we report a case of ETT with detailed macroscopic and imaging findings.

A 39-year-old woman with positive pregnancy test results was admitted to a nearby hospital. No gestational sac was found in the uterus, and magnetic resonance imaging (MRI) revealed a cystic mass of approximately 7 cm that extended continuously from the anterior wall of the lower uterine segment into the pelvic cavity. She underwent laparoscopic and hysteroscopic surgeries for a ruptured cervical pregnancy. Pathology of the specimens obtained from this surgery did not allow for the diagnosis of ETT. Two months after the surgery, as the serum human chorionic gonadotropin β subunit (β-HCG) level did not decrease, she was diagnosed with low-grade gestational trophoblastic neoplasia, leading to the administration of chemotherapy. After three regimens of chemotherapy over 9 months, her β-HCG level decreased but did not reach normal levels. Ultimately, a total hysterectomy was performed. The pathological diagnosis was mixed ETT and choriocarcinoma. A literature review revealed several cases similar to ours.

ETT in the lower uterus often perforates the myometrium and forms cystic lesions in the retroperitoneal space or subserosa. The MRI and laparoscopic/hysteroscopic findings in this case may have contributed to the early diagnosis of ETT.