Challenging, Giant Occipital Encephalocele in A Pediatric Saipanese Male

Introduction: An encephalocele is a type of cranial dysraphism characterized by herniation of intracranial contents including meninges, brain, blood vessels, and ventricular components through a midline calvarial defect. As a rare form of neural tube defect, their etiology involves defective embryogenesis that can occur spontaneously or in association with early gestational exposures. A rare form of congenital anomaly, giant occipital encephalocele involves protrusion of brain tissue from a defect in the skull (in this case from the occiput). While encephalocele itself is a fairly rare entity, those qualifying as “giant”—defined by size of the deformity exceeding that of the skull itself—require very technically challenging surgery.

Case Illustration: We present a newborn Saipanese male with limited prenatal care who presented to our institution with a giant occipital encephalocele with intact overlying dermis and pedunculated base. Neurological exam was unremarkable. An MRI was obtained and showed a giant encephalocele sac containing a large amount of dysplastic brain tissue and ventricular components with a robust vascular supply as demonstrated on MR venogram. After fiberoptic intubation the patient was placed prone in a horseshoe headrest taking care to support the encephalocele manually during positioning, prepping, and draping to avoid tearing or rupture. A circumferential incision is made just below the equator of the lesion and dissection is carried anteriorly and circumferentially toward the calvarial defect being careful to remain in the dysplastic subcutaneous plane outside the neural tissue to minimize blood loss. Once the root of the encephalocele with its vascular supply is isolated around a perimeter, it is ligated with heavy silk suture at the base. Given the size of the encephalocele, it was determined that attempting to internalize the encephalocele material into the calvarium could place the native and ostensibly more normal neural structures at risk. Therefore, the encephalocele was truncated at its pedunculated base which appeared highly vascular and disorganized. The dysplastic tissue was then resected leaving a ligated end which is internalized and covered with native dura that was freed surrounding the defect. The patient remained hemodynamically stable during the perioperative and postoperative course and was extubated. Following the encephalocele repair, head circumference and transfontanelle ultrasound results were tracked on a daily basis. This demonstrated increasing head circumference through growth curves and increasing ventricular size consistent with hydrocephalus. As a result, the decision was made to place a cerebrospinal fluid shunt in delayed fashion for unresolved hydrocephalus. At the time the shunt was placed (within 3 weeks postoperative), there were no signs of CSF leak, visual acuity deficits, or wound infection. Of note, hydrocephalus is commonly reported in conjunction with giant encephaloceles. As such, it was not thought to be a complication of the surgical intervention or the result of bleeding or other iatrogenic cause, but rather a feature related to the natural history and constellation of pathology associated with occipital encephaloceles.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
05 February 2024