뇌유의 2부검증례

Abstract

Two autopsy cases of encephaloceles were reported. The first case was a female baby died in one day and had a huge occipital mass containing posteri"r two thirds of cerebrum. midbrain, pons and medulla oblongata. An unexplained polypoid mass of cerebral tissue was seen at parasagittal area of left parietal lobe. Tentorium cere belli was absent. Subarachnoid vessels were congested. The encephalocele was covered by dura and skin. Occipital bone had a huge defect. The subcutaneous tissue over the encephalocele had multiple nests of neuroglial cells without connection to the brain proper. Cut sections of the brain showed enlargement of left lateral ventricle. Focal hemorrhage and calcification were present at occipital lobe. The second case was a female baby died soon after birth. She had a cystic, polypoid mass at right forehead. Right eye was replaced downward and nares were separated apart. Median cleft lip was also present. Right half of frontal bone was completely defective, a small portion of through which frontal lobe was herniated. Cystic cavity of the frontal mass was a continuation of right lateral ventricle. Falx cerebri was hypoplastic, thalami fused to each other and Arnold-Chiari type I anomaly was associated. Cut sections showed bilateral hydrocephalus especially at right lateral ventricle. The encephalocele was covered by skin and dura. Skeletal muscle was partly incooperated and was splitted. Anterior lobe of pituitary gland showed abnormal capsulation with fibre-collagenous capsule and septation. Classical theories explaining the pathogenesis of encephaloceles were proposed by Geoffrey-SaintHillaire( 1827) and Spring(l853). They were incomplete separation of ectodermal germ layers and increased intracranial pressure. But disputes on the pathogenesis are still present. Major disputes are summarized as: 1. Whether the brain tissue in encephalocele is herniated tissue or heterotopic tissue? 2. Is there any evidence explaining the classical theory of Geoffrey-Saint- Hillaire? 3. Is the increased intracranial pressure a primary defect or secondary phenomenon? 4. Local ischemia in skull and adjacent soft tissue makes the defect to give harniating pathway, is it true? We reviewed the literature and tried to explain them based on the findings of our cases.