Abstract
The clinical and pathologic features of two cases of placenta percreta were reviewed. The findings were compared with three cases of normal implantation obtailned by matching the patients' age and the gestational age. Two abnormal implantations showed the absence of decidua and the interruption of Nitabuch's fibrinoid layer in the areas of deepest chorionic invasion., The surface of penetrating trophoblast was negative for beta-human chorionic gonadotropin immunostaining in both placenta percretas but positive in normal implantations; however, reverse transcriptase-polymerase chain reaction analysis of RNA extracted from the same sites demonstrated the presence of beta-human chorionic gonadotropin in RNA obtained from both normal and abnormal implantations. These findings suggest that trophoblastic invasion in placenta percreta may be related to a post-transcriptional defect in beta-human chorionic gonadotropin synthesis.