GTD (gestational trophoblastic disease) is a set of diseases caused by trophoblastic cells. Invasive mole, choriocarcinoma, and placental site trophoblastic tumor are also included in this category.
Invasive mole is caused by edematous chorionic villi extending into the myometrium. It is typically locally invasive [1], but metastatic cases have been documented in the literature [2, 3]. It occurs in 1 in every 15,000 pregnancies, and it frequently occurs after a molar pregnancy. It can often be diagnosed without histopathological evaluation, when a patient has vaginal bleeding and prolonged high b-hCG values after postmolar pregnancy [4]. However, histopathologic analysis of the chorionic villi in the myometrium can provide a definitive diagnosis [5]. In comparison with choriocarcinoma and PSTT, it is seen less frequently following a healthy pregnancy [1, 5].
GTNs are characterized by prolonged vaginal bleeding and elevated b-hCG levels in blood testing. The uterine sizes are larger than normal, according to the physical examination. However, postpartum bleeding is a common problem. So GTN may be included in the differential diagnosis when persistent b-hCG increase and prolonged vaginal hemorrhage are present [4]. After clinical suspicion, ultrasonography (US) should be the initial imaging modality used. In grayscale ultrasonography, GTNs cannot be separated from one another and appear as a heterogeneous mass in the myometrium. Small anechoic focal regions, which signify bleeding, cysts, or necrosis, are common. Color Doppler ultrasonography (CDUS) examination reveals increased vascularity in the tumor. Ultrasound is followed by MRI, which is a more sensitive diagnostic tool. GTNs appear on MRI as a mass lesion in the myometrium that is T1WI isointense, T2WI hyperintense, and surrounded by a hypointense rim. Increased vascularity can be seen on T2WI as loss of signal voids in the mass. After intravenous gadolinium administration, the mass enhances intensely. In the evaluation of extrauterine invasion and lymph nodes, MRI surpasses ultrasonography [5].
Due to the hypervascular pattern, arteriovenous malformation and interstitial pregnancy must also be evaluated in the differential diagnosis. GTN can be distinguished from the other by the absence of fetal material in the uterus and high β-hCG values in the laboratory test [2].
Chemotherapy is the first line of treatment for invasive disease, and it should be continued until three consecutive normal b-hCG values are observed. After the b-hCG levels return to normal, three further rounds of chemotherapy are given to lower the chances of recurrence. If bleeding cannot be managed, hysterectomy can be performed [3].