Uterine mass after caesarean section: a report of two cases

BACKGROUND: Caesarean scar pregnancy (CSP) is a rare complication of caesarean delivery and a special type of ectopic pregnancy. Gestational trophoblastic neoplasia (GTN) is an uncommon complication of pregnancy. Early diagnosis of the two diseases is crucial because a delay or misdiagnosis can lead to increased maternal morbidity and mortality. CASE PRESENTATION: We report two cases of uterine isthmus lesions with a previous caesarean section (CS). Two patients were misdiagnosed based on the first ultrasound exam. The first case of trophoblastic tumour was initially diagnosed as CSP, while the second case, which had a scar pregnancy, was misdiagnosed as GTN. The misdiagnoses were due to the particularity of the locations of the lesions in the two patients, complicating the ultrasound-based diagnosis and hindering early clinical diagnosis and treatment. CONCLUSIONS: A medical history, β-hCG measurements and transvaginal ultrasound are necessary to diagnose lesions in the lower anterior wall of the uterus early. However, when the location cannot be determined, magnetic resonance imaging (MRI) can be further performed to determine whether the lesion is located at the uterine scar. Combined with the degree of increased β-hCG, differentiate CSP, myometrial GTN or caesarean scar GTN is helpful.