[Porencephaly. Case report].

A case of porencephaly in a 33-year-old male is presented. The patient exhibited right hemiparesis and generalized seizures. Computed tomography and, subsequently, craniotomy revealed a cerebral defect in the left parietal lobe, which communicated with the lateral ventricle. On angiography and at surgery, the cortical branches of the middle cerebral artery were found to be stretched over the surface of the cyst. Histopathological examination showed the outer membrane of the cyst to consist of arachnoid, subarachnoid space, vessels, pia mater, and a layer of degenerative brain tissue on histology. The diagnosis of porencephaly and its differentiation from arachnoid cyst are discussed.