Case report: Two rare uterine cesarean scar mass cases

Gestational trophoblastic neoplasia (GTN) located in the cesarean scar is a rare disease that has imaging appearances similar to those of an exogenous scar incision pregnancy and is often misdiagnosed due to insufficient clinical experience. PATIENT CONCERNS: We report 2 cases of uterine cesarean scar mass. Two patients with different diagnoses had similar clinical complaints as abnormal vaginal bleeding, enlargement of uterus isthmus by physical examination, and mixed echo mass in uterine low segment by ultrasound examination; however, their magnetic resonance imaging images showed very different features. DIAGNOSES: One patient was diagnosed with cesarean scar pregnancy (CSP) and one patient was diagnosed with cesarean scar GTN. INTERVENTIONS: The CSP patient underwent surgery by laparoscopy combined with hysteroscopy after uterine artery embolism and obtained pathological confirmation. The GTN patient received chemotherapy. OUTCOMES: For the CSP patient, her serum β-human chorionic gonadotropin (hCG) concentration returned to normal 2 weeks later, and B-ultrasound showed that the niche was completely repaired 3 months after the operation. The intrauterine lesions of the GTN patient disappeared completely 3 months after serum β-hCG normalization. And her β-hCG was normal at all follow-up visits until now. LESSONS: Clinicians should consider GTN when identifying masses at scar incision sites. Magnetic resonance imaging images improve the understanding of the imaging features in patients suspected of having CSP/GTN.