What is a characteristic feature of an encephalocele?

A characteristic feature of an encephalocele is the brain protruding through the skull contained in a sac. Encephaloceles are neural tube defects that involve abnormal skull formation, leading to herniation of brain tissue and meninges (the protective membranes covering the brain) through an opening in the skull. This condition is often associated with brain tissue being exposed or protected by a fluid-filled sac.

The presence of a sac that contains brain tissue is a defining element of encephalocele, distinguishing it from other conditions that might affect the skull or brain but do not involve this specific protrusion. Understanding this feature is crucial for diagnosis and management, as it requires specific surgical intervention to repair the defect and protect the brain tissue.

Other options describe different medical conditions or features. For example, overgrowth of facial bones is associated with other craniofacial syndromes, a gap in the spine relates to spina bifida, and shortened long bones can apply to various forms of skeletal dysplasia. None of these accurately describe encephalocele, reinforcing that brain protrusion in a sac is the hallmark of this particular malformation.