Pathogenesis of Ectopic Pregnancy: The Inherent Role of Trophoblasts

Objective: We sought to determine if characteristics of hydatidiform molar change were present in the trophoblastic tissue of ectopic pregnancies. We also evaluated the type of pathology found on tubal sections adjacent to the ectopic pregnancy. Materials and Methods: One hundred fallopian tube specimens from patients who had undergone total or partial salpingectomy for ectopic pregnancy between January and December 2000 were studied. Each specimen was microscopically evaluated for the presence or absence of trophoblastic hyperplasia, hydropic villi, and fetal blood vessels. Adjacent tubal sections were examined for evidence of tubal pathology. Results: Of the 100 ectopic pregnancies, 18 were excluded for inadequate sampling and poor quality. Twenty-five (30.5%) of the remaining 82 cases showed trophoblastic hyperplasia. Thirty-eight (46.3%) showed hydropic villi. Fetal blood vessels were not evident in 26 (31.7%) of the specimens. There was no evidence of trophoblastic atypia in any of the specimens. Fifteen (18.3%) specimens showed both trophoblastic hyperplasia and hydropic villi. Of the 15 specimens that had both of the above characteristics, only 1 did not have fetal blood vessels. Only 40 (48%) of the samples had evidence of fallopian tube inflammatory disease in sections adjacent to the ectopic pregnancy. Of these, 23 (57%) were normal, 13 (32.5%) showed chronic salpingitis, 3 (7.5%) showed acute salpingitis, and 1 (2.5%) showed salpingitis isthmica nodosa. Conclusion: Eighteen percent (18%) of our specimens obtained from salpingectomy in ectopic pregnancy showed characteristics of hydatidiform molar change in the trophoblastic tissue. Thirty and one-half percent (30.5%) and 46.3% had trophoblastic hyperplasia and hydropic villi, respectively. These changes show that inherent ovum pathology is associated with tubal pregnancy in numbers equal to chronic salpingitis.