Old ectopic pregnancy remnants with morphological features of placental site nodule occurring in fallopian tube and broad ligament

Placental site nodule (PSN) is an asymptomatic benign proliferation of intermediate trophoblast from a previous gestation that failed to involute. It is most commonly found in the endometrium or endocervix; however, placental site nodule has recently been reported to occur at sites of ectopic gestation. This is the first case of PSN ill the broad ligament in direct contact with the fallopian tube. The patient underwent surgery for an adenocarcinoma of the opposite tube. Microscopically and immunohistochemically, the lesion showed the characteristics of a proliferation of intermediate trophoblast.