Placental site trophoblastic tumour mimicking an intramural pregnancy: a case report and review of the literature

Gestational trophoblastic disease (GTD) covers a range of proliferative disorders from non-neoplastic hydatid moles to malignant neoplastic conditions such as choriocarcinoma. The incidence of these diseases is low and often challenging to diagnose. Placental site trophoblastic tumour (PSTT) is the rarest form of GTD, accounting for up to 3% of all cases. We present a case of a 35-year-old patient diagnosed with PSTT mimicking an intramural pregnancy. Placental site trophoblastic tumour occurred after pregnancy, which ended as a blighted ovum. β-hCG was not very high, and the patient had no complaints. The diagnosis was made after resection of formation which was accepted for intramural pregnancy. To our knowledge, this is the first such case described in the literature. A hysterectomy performed later confirmed the absence of a residual tumour after conservative intervention. The lack of distant metastases, confirmed by positron emission tomography-computed tomography scan, allowed for only hysterectomy with bilateral salpingo-oophorectomy to be performed. The patient was classified as low risk according to the World Health Organization (WHO) scoring system. Placental site trophoblastic tumour is a rare malignant tumour (despite its WHO coding) from the group of GTDs. It is not presented with a classic clinical picture, and its clinical diagnosis is challenging. However, clinicians should consider it in the case of unclear events after any type of pregnancy.