Treatment of heterotopic caesarean scar pregnancy complicated with post termination increase in size of residual mass and morbidly adherent placenta.

We report a case of a secundipara with heterotopic cesarean scar pregnancy (HCSP) treated with potassium chloride injection into the ectopic embryo followed by sac aspiration. The remaining "mass" increased in size threefold and was surrounded by a rich vascular network. An arteriovenous malformation was suspected; however, appropriate treatment was precluded because of the viability of the ectopic gestation. Sonographic examination revealed a morbidly adherent placenta, and attempt to resect the mass laparoscopically was complicated by bleeding that required hysterectomy. This case illustrates a complication of the intervention performed to preserve the intrauterine gestation in case of HCSP. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:227-230, 2018.