[Diagnosis of an ectopic pregnancy on a cesarean scar].

We report the diagnostic and therapeutic debate raised by an ectopic pregnancy on a cesarean scar. There were three phases. The first was to differentiate between an ongoing abortion and an ectopic pregnancy on a cesarean scar. The second was to determine whether the tissue was a mass of persistent trophoblasts or an invasive mole. Finally to determine the nature of a residual mass after chemotherapy and normalization of the beta CG level.