A case of a large occipital encephalocele presenting with delayed hydrocephalus pathology

Abstract

A female neonate was born at term with congenital large skin-covered occipital encephalocele. Magnetic resonance (MR) imaging at 3 days of age showed brain parenchyma protruding extracranially from a bony defect in the parieto-occipital region, and the size of the mass was 70 mm in diameter. She underwent resection of encephalocele and cranioplasty. Postoperative computed tomography (CT) showed no hemorrhage or hydrocephalus. MRI 6 months after resection of encephalocele revealed enlarged ventricular structures and multiple cysts, and she underwent cysto-peritoneal (CP) shunt, fenestration of cysts and cranioplasty. Preoperative imaging studies are important to evaluate for the presence of protrusion of lateral ventricular structures and vascular inflows into the encephalocele. A large encephalocele must be amputated at the base, as a brain protruding outside the cranium is considered to have lost significant neurological function. If the bone defect is not covered with an absorbable plate or other material during the initial surgery, there is a risk that the brain will protrude again postoperatively. In addition, hydrocephalus is likely to occur in the chronic phase and careful follow-up is essential. Since cranial defects never form spontaneously, it is advisable to perform cranioplasty with an autogenous bone fragment as a rotational flap with periosteum during the secondary surgery, if possible. The key points of our surgical technique are described in detail.