Cyclopia Syndrome with Neck Presentation: A Case of Alobar Holoprosencephaly and Prenatal Diagnostic Challenges

Alobar holoprosencephaly is the most severe and common subtype of holoprosencephaly (HPE), a developmental defect that arises during the embryonic period due to heterogeneous factors. This condition is characterized by incomplete development and separation of the forebrain, often accompanied by facial deformities, especially in severe cases. Most severe cases result in stillbirth or neonatal death shortly after delivery. We report a case of a 28-year-old multiparous woman who presented with preterm labor and preterm premature rupture of membranes (PPROM). Ultrasound imaging revealed fetal malformations consistent with alobar HPE, including cyclopia syndrome. The patient delivered a stillborn infant vaginally in an unusual neck presentation. We discuss the etiology of HPE, including potential contributing factors such as toxoplasmosis in our case, along with diagnostic and management considerations. Additionally, we highlight the special presented part of the infant during vaginal delivery and its possible reasons. Early prenatal diagnosis of cyclopia syndrome is crucial, as it significantly impacts family counseling regarding pregnancy continuation. It also underscores the need for additional genetic and serological viral tests to investigate potential underlying causes.