A case of fetal twin-to-twin cytomegalovirus infection through a dichorionic diamniotic (DiDi)-fused placenta prompted our search for possible vascular anastomoses in this type of placenta. This case and three additional DiDi-fused placentas were studied with gross (macro) sections and a three-dimensional (3D) stereomicroscopic technique. Two twins were dizygotic (they differed in gender and blood groups) and the other two were probably monozygotic. Macrosections and 3D-image analysis demonstrated side-to-side connections between small subchorionic vessels. These findings demonstrate that vascular anastomoses are present in DiDi-fused placentas.
From the Departments of Anatomic Pathology (M.P.F., T.D.), Ospedale Bellaria, Preventive Pediatrics and Neonatology (M.L.), and Clinical and Experimental Medicine (L.G., T.L., M.P.L.), Section of Microbiology, University of Bologna, Bologna, Italy; and the Department of Gynecologic and Perinatal Pathology (M.K.), Clinical Hospital Center Zagreb, Croatia.
Address correspondence and reprint requests to Maria P. Foschini, Anatomia Patologica, Ospedale Bellaria, Via Altura, 3, 40139 Bologna, Italy.