Histopathological findings of ectopic pregnancy in contraceptive-wearing women

In a normal pregnancy, the egg is fertilized in the fallopian tube. Afterward, it moves into the uterus, where it implants into the uterine endometrium. However, if the fallopian tubes are narrow or blocked, the fertilized egg cannot move into the endometrium. In this situation, the fertilized egg implants in tissue other than the uterus, resulting in an ectopic pregnancy. In most cases of ectopic pregnancy, the fertilized egg implants in the left or right fallopian tube. It can also implant in tissues other than the fallopian tubes, such as the ovary. This paper presents our experience in treating a 37-year-old woman who had a tubal pregnancy despite wearing a contraceptive. Contrast-enhanced magnetic resonance imaging showed a gestational sac behind the right fallopian tube. Laparoscopic surgery was performed to resect the right fallopian tube. Pathological examination suggested that the ectopic pregnancy occurred at the organogenesis stage 9 weeks after fertilization. The pathological findings revealed subpopulations of cells from the ectoderm that were separated from other cells and more specifically formed spinal and ovarian structures. This paper presents valuable surgical pathological findings for understanding the differentiation into each tissue during the organogenesis stage.