The pathology of placenta accreta, a worldwide epidemic.

The incidence of placenta accreta, defined as the abnormal adherence of the placenta to the uterine wall, has been increasing alarmingly in the developed as well as the developing world. There is considerable maternal morbidity and mortality related to the condition. The pathophysiology focuses on the balance between decidualisation on the one hand and trophoblast invasion on the other. Pathological diagnosis relies on the finding of placental villi in direct apposition to myometrium, either in hysterectomy specimens or in placental basal plates.