Encephaloceles are usually named by where they occur on the skull. Location is one of the most important things to understand, because it strongly influences appearance, treatment, and outlook.
Why location is the headline
Encephaloceles form along the midline of the skull, and the spot where the closure problem occurred determines the type. Location matters because it affects what brain structures might be involved, how visible the defect is, how it's repaired, and the general outlook.
The main types
Occipital encephalocele (back of the head) The most common type in the Western world (roughly three-quarters of cases). The sac sits at the back of the skull. Because it can involve significant brain tissue and is associated with hydrocephalus, the outlook depends heavily on what's inside.
Parietal encephalocele (top of the head) Less common; sits higher on the skull. Outlook varies but is often more favorable than occipital when little brain tissue is involved.
Frontal / frontoethmoidal / sincipital (front of the head and face) Located around the forehead, between the eyes, and the nose. More common in parts of Asia. These often cause visible facial differences (like wide-set eyes) and may need craniofacial reconstruction.
Nasal encephalocele (nose region) A small portion of cases. Can look like a bump on or inside the nose, and is sometimes confused with other nasal masses — making correct diagnosis crucial.
Basal / transsphenoidal encephalocele (skull base, internal) Rare and "hidden," because the sac protrudes inward toward the nose/throat rather than outward. May not be visible and can cause symptoms like nasal blockage.
Atretic encephalocele (small, often on the scalp) A very small, often mild form, frequently appearing as a small scalp nodule. Many do well, though imaging is still important.
Region matters: a global note
In the Western Hemisphere, occipital (back) encephaloceles dominate. In parts of Southeast Asia, anterior (front/nasofrontal) encephaloceles are far more common. This is why you may see different "most common type" statements depending on the source's region.
Sources
- CDC — Encephalocele (Birth Defects)
- Cleveland Clinic — Encephalocele
- NORD — Encephalocele
- StatPearls (NCBI Bookshelf) — Encephalocele
- Boston Children's Hospital — Encephaloceles