A donor twin discordant with Peters anomaly in a twin–twin transfusion syndrome case: a case report

BACKGROUND: Peters anomaly is a rare form of anterior segment ocular dysgenesis, the antenatal image of Peters anomaly had not been reported. We herein showcased a discordant finding of Peters anomaly in a monozygotic twin complicated with twin-twin transfusion syndrome (TTTS) and exhibited its antenatal sonographic images, CASE PRESENTATION: A 38-year-old gravida 2 para 1 pregnant woman visited our clinic at the gestational age of 18 weeks where TTTS stage III was diagnosed and the following laser therapy was done successfully. Ten days after the surgery, the follow-up ultrasound detected the opacity of both fetal eyeballs in the donor twin and thus congenital cataract was suspected initially. Then magnetic resonance imaging (MRI) examination was arranged at the gestational age of 23 weeks, and no central nervous system or other anomaly was found. At the 29 weeks of gestation, the opacity of both fetal eyeballs of the donor twin did not clear. The pregnancy resulted in cesarean section at the gestational age of 37 weeks indicated by malpresentation where two male live births were born. Examination under anesthesia was arranged for donor twin after delivery and Peters anomaly was diagnosed based on central corneal opacity with iridocorneal and corneolenticular adhesions. CONCLUSIONS: The prenatal image of Peters anomaly may present as the opacity of the fetal eyeballs similar to congenital cataract. Some cases of the Peters anomaly had been reported with a genetic abnormality, but since our case presented discordant presentation in monozygotic twin pregnancy where both twins are supposed to share the same genetic make-up, therefore other factors that are epigenetic may be held accountable. Nevertheless, a genetic origin of the anomaly in our case cannot be excluded.