ECTOPIC PREGNANCY - HISTOPATHOLOGY AND ASSESSMENT OF CELL-PROLIFERATION WITH AND WITHOUT METHOTREXATE TREATMENT

Objective: To evaluate tubal morphology, trophoblast proliferation, an d inflammatory reaction in response to methotrexate (MTX) treatment of ectopic pregnancy (EP). Design: Nonrandomized controlled study. Setti ng: Academic hospital. Patients: Archival specimens from 10 EP unsucce ssfully treated with MTX and 10 cases primarily treated by surgery. In terventions: Ki67/hCG and Ki67/human placental lactogen double immunoh istochemical methods were used to examine trophoblastic spread, placen tation, hormone production, decidualization, vascular invasion, hemorr hage, rupture, and proliferative index of the cytotrophoblast. B and T -lymphocyte responses were evaluated by CD3 and CD20. Results: Trophob lastic spread and placentation were confined to the tubal mucosa after MTX treatment, whereas invasion of the muscularis and subserosa was c ommon in the controls. The proliferative index was reduced (19% versus 93%), although a high proliferative index was found in two of three c ases complicated by rupture. Polar proliferation of Ki67-positive cyto trophoblast toward the implantation site was abolished in MTX-treated cases. Decidual reaction was not observed. No correlation was observed between the above-mentioned findings and gestational age, level of be ta-hCG, dose of MTX, or interval to surgery. Conclusion: Trophoblastic spread, differentiation, and invasion were compromised by MTX treatme nt. Methotrexate seems to decrease cytotrophoblast proliferation. Whet her a missing decrease in proliferation index reflects treatment failu re awaits a larger population-based study.