Cephalopagus is the rarest type of conjoined twins. Early antenatal diagnosis is important in view of extremely poor prognosis as surgical separation is not possible in such cases. Fetal MRI is an excellent complementary tool to prenatal sonography in assessment of complex fetal anomalies.

Dyke-Davidoff-Masson syndrome (DDMS) is an uncommon congenital/pediatric disorder diagnosed only with the help of imaging. Clinical features associated with it are hemiparesis, seizures, facial asymmetry, and mental retardation. We here present a case of DDMS diagnosed antenatally at 29 weeks gestational age during routine antenatal ultrasound examination. The patient was further evaluated and followed using both ultrasound and magnetic resonance imaging during antenatal and postnatal periods. The infant had unilateral hemiatrophy with the absence of anterior and middle cerebral arteries. We hereby also want to coin the term "shifted falx sign" as a diagnostic indicator for DDMS for the first time. To our knowledge, this is the earliest antenatally sonologically diagnosed case of the said pathology.

Congenital brain tumors, especially tumors diagnosed before birth, are very rare. This article describes a case of primitive neuroectodermal tumor (PNET) diagnosed by ultrasonography at 24 weeks of gestation. Follow-up ultrasound study and MRI at 27 weeks of gestation revealed aggressive growth and complications of tumor. The diagnosis was confirmed at autopsy. Prenatal diagnosis of PNET or other congenital brain tumors is important because the presence of tumors may alter the time and mode of delivery and planning of postnatal care.