Histopathological Findings of Ectopic Pregnancy in Contraceptive-Wearing Woman

In normal pregnancy, the egg is fertilized in the fallopian tube. It later moves into the uterus, where it implants into the uterine endometrium. Therefore, implantation of the fertilized egg into the endometrium is not observed in many women using contraceptives. However, if the fallopian tubes are diseased or abnormal, the fertilized egg cannot travel to the endometrium. Thus, the fertilized egg is implanted in tissues other than the uterus, resulting in an ectopic pregnancy. In most cases of ectopic pregnancy, the fertilized egg is implanted into the left or right fallopian tube or in tissues other than the fallopian tubes such as the ovary. With laparoscopic surgery, the scars are small, and the pain and physical burden are also much lesser than those with open surgery; thus, the patient can be rehabilitated immediately. Laparoscopic surgery is preferred for the termination of ectopic pregnancies because the patients recovered quickly physically after surgery and can be discharged in a short period. This paper presents our experience in treating a 37-year-old woman who had a tubal pregnancy despite using a contraceptive. Contrast-enhanced magnetic resonance imaging showed a gestational sac within 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. The implantation of the fertilized egg into the endometrium is not observed in many women using contraceptives. However, in rare cases, ectopic pregnancy occurs in women using contraceptives; thus, caution is necessary in diagnosis and treatment. This report presents valuable surgical pathological findings from such a rare case of ectopic pregnancy to understand the differentiation into each tissue during organogenesis.