Cornual Epithelioid Trophoblastic Tumor: A Report of a Rare Case and Literature Review.

Cornual ectopic pregnancy is a rare type of ectopic pregnancy that occurs in the cornua of the uterus. This condition poses significant risks, including rupture and severe hemorrhage, making early diagnosis and management crucial. Gestational trophoblastic neoplasm (GTNS) is a spectrum of malignant diseases including invasive mole, choriocarcinoma, placental site trophoblastic tumor (PSTT), and epithelioid trophoblastic tumor (ETT). ETT is a rare type of gestational trophoblastic tumor. While ETT shares some similarities with other trophoblastic tumors, it has distinct histological features, clinical behaviors, associations, and treatment approaches that set it apart. We present a rare case involving a 38-year-old Saudi woman diagnosed with a cornual ectopic pregnancy, which was later histopathologically confirmed as ETT. Initial treatment included systemic and local methotrexate, but the patient exhibited persistently elevated beta-human chorionic gonadotropin (β-hCG) levels, necessitating surgical intervention. A wedge resection of the cornual ectopic mass was performed, and histopathological analysis confirmed the diagnosis of ETT. Postoperative imaging indicated small bilateral pulmonary nodules that raised concerns for metastasis. The patient underwent multi-agent chemotherapy, beginning with methotrexate and later transitioning to dactinomycin due to insufficient decline in β-hCG levels. After three cycles of dactinomycin, β-hCG levels returned to normal. This case emphasizes the diagnostic difficulties associated with ETT and highlights the critical role of histopathological examination for patients with persistent β-hCG elevation. In this instance, surgical resection followed by multi-agent chemotherapy proved to be an effective treatment approach. We reported this case because of its rarity and diagnostic and therapeutic challenges.