Subserosal pregnancy in a previous myomectomy site: a variant of intramural pregnancy

A 35-year-old woman with a history of myomectomy underwent in vitro fertilization and became pregnant. Transvaginal ultrasound revealed a gestational sac within the subserosal area of the posterior uterine wall. The patient was treated successfully with conservative surgery, and the pathologic evaluation of the excised mass demonstrated chorionic villi involving myometrium. Early in a subsequent pregnancy, placental invasion through the sinus tract was detected. However, the pregnancy outcome was uneventful. This constitutes the first report of subserosal implantation in the uterine body. Our findings suggest that the probable pathogenesis of this rare variant of intramural pregnancy is implantation through a sinus tract made during a previous uterine surgery.