Exaggerated placental site reaction detected during caesarean delivery: a case report.

Exaggerated placental site (EPS) reaction is an exuberant physiologic process in which intermediate trophoblasts infiltrate the underlying endometrium and myometrium at the implantation site. During a caesarean section, we noted a polypoid well shaped smooth lesion, about 3 cm in diameter on the anterior wall of the uterus apart from the placenta. The histopathologic examination revealed an exuberant proliferation of trophoblastic cells in the placental site, a low Ki-67 labelling index and the absence of mitotic activity. Distinguishing EPS reaction from the other intermediate trophoblastic tumours is critical, as the latter may likely involve surgical intervention and/or chemotherapy, although no specific treatment and follow-up is required for EPS reaction. It is necessary to be aware of this pathology and take biopsies from suspicious lesions in the placental site for pathologic examination.