Association of chorangiomas to hypoxia-related placental changes in singleton and multiple pregnancy placentas

Introduction Chorangiomas (CAs) are the most frequent non-trophoblastic tumor-like-lesions of the placenta, and since they occur with an unusual frequency in pregnancies at high altitude, they are considered as a part of a spectrum of hypoxia-related vascular lesions of the placenta. The aim of our study is to describe the morphological features of the CAs and to show associations between CAs and other hypoxia related morphological changes in placentas of singleton and multiple pregnancies. Materials and methods Placentas from singleton (121 vs 242) and multiple (49 vs 98) pregnancies, with and without CAs, respectively, were selected from a cohort of 15,742 placentas and enrolled into a case control study. Results Singleton placentas with CAs showed increased incidence of hypoxia-related placental changes including accelerated maturation of chorionic villi (OR = 2.40, p < 0.001), infarction (OR = 2.89, p < 0.001), decidual arteriopathy (OR = 3.24, p < 0.001), fetal thrombosis (OR = 4.05, p < 0.001) and hypercoiled umbilical cords (OR = 5.55, p < 0.001). The incidence of CAs in multiple placentas was higher in our studied cohort and a significant associated change was shown with fetal thrombosis (OR = 4.58, p = 0.017). There were no significant morphological changes between CAs in singleton compared to multiple pregnancies. Discussion In singleton placentas, CA is associated with several placental changes related to hypoxia, whereas in multiple pregnancies this relationship is not present. We speculate that CAs in multiple pregnancies might reflect an adaptive mechanism for relative hypoxia per se in these pregnancies. Conclusion Our study provides evidence that CAs are associated with an increased rate of hypoxia related changes in singleton placentas.