Placenta with Old, Diffuse Infarction that Was Difficult to Differentiate from a Placental Tumor.

Placental lesions, including placental infarction, are associated with fetal and neonatal mortality and morbidity. We present a case of fetal growth restriction associated with an old, diffuse placental infarction. Because the placenta had only a single viable cotyledon, the others being atrophic, the lesion appeared to be a placental tumor on prenatal ultrasonography. The patient did not have pregnancy-induced hypertension. At 31 weeks of gestation, a cesarean delivery was performed because of fetal growth arrest and breech presentation. A small-for-gestational age infant was delivered with Apgar scores of 8 at both 1 and 5 minutes, and the infant had cleft palate and cleft lips. Pathological examination of the placenta revealed an old, diffuse infarction without neoplastic change. In cases in which a placental tumor causing fetal growth restriction is strongly suspected, diffuse placental infarction should be considered as part of the differential diagnosis, because placental tumors are associated with poor maternal prognosis.