Retained trophoblastic tissue in fallopian tubes: a consequence of unsuspected ectopic pregnancies.

Five patients had retained trophoblastic tissue within the Fallopian tubes, which suggested remote ectopic pregnancies. Four remote ectopic pregnancies were identified in patients after delivery. One patient underwent salpingo-oophorectomy after the identification of a small ovarian mass and 1.0 cm "necrotic area" in the fallopian tube at cesarean section. The other three patients underwent tubal ligation, and one was noted to have a 1.0 cm "calcified" nodule in the distal fallopian tube. The fifth patient underwent laparotomy and was found to have an acute ectopic pregnancy in one fallopian tube and a clinically unsuspected 3.0 cm mass in the other, which proved to be an ectopic pregnancy with ghost outlines of chorionic villi and trophoblast. Histopathologically, all five patients showed foci of viable-appearing intermediate trophoblast and surrounding abundant eosinophilic hyalinized material in the fallopian tubes; four patients also had hyalinized ghost outlines of chorionic villi. None of the mothers had a history of previous ectopic pregnancy. The natural history of clinically unsuspected ectopic tubal pregnancies is not well understood, but these cases illustrate that trophoblast may persist in fallopian tubes and potentially result in clinical confusion as well as tubal pathology.