Discussion
The placenta may show various types of cystic structures, which can be broadly categorized into septal cysts, in which the cysts are located within placental tissue, and the more rarely encountered subchorionic, or true placental cysts, which are located under the fetal plate. These cysts are usually single but may be multiple. True placental cysts are rare with a prevalence of 2% to 7%. Their etiology is unknown, but they are more common in diabetes or in cases of maternofetal rhesus incompatibility. These cysts are usually asymptomatic, with the most common complication being intrauterine growth retardation. Their location near the cord site may lead to umbilical cord constriction and compromise of fetal blood flow. Rarely, these cysts may cause intrauterine fetal asphyxia and death.