Neurological signs and operative indication by agenesis of the perisylvian region: a study of 13 operated cases

Abstract

The first signs of Sylvian Depression in embryogenesis may be detected at the end of the second intrauterine month and become more apparent as a Sylvian groove at the end of the third month. The temporal operculum grows more effectively in the anterior two thirds and reaches the Sylvian fissure in the fourth month. At the same time the fronto-parietal operculum becomes evident and gradually extends backwards to meet the anterior part of the temporal operculum. These changes occur in the later half of the fifth month. Because the growth of the temporal operculum is more intense than that of the fronto parietal one, it follows that, when the opercula meet in the sixth intrauterine month, there is more of the Sylvian area covered by the temporal than by the fronto-parietal operculum. (Fig. 1) The present syndrome (Agenesis of the perisylvian region) is considered to be a disturbance of this cerebral embryogenesis and becomes evident during the last three months of foetal life. Arachnoid cysts are to be found in the hypoplastic region, sometimes with space occupying character. 70 cases of agenesis of the fronto-temporal area with diagnosis was mostly made during operation. The patients were operated under the tentative diagnosis of a space occupying lesion like subdural haematoma, external hydrocephalus, porencephaly, intracerebral haematoma or tumor.Before the syndrome of agenesis of the perisylvian region had been com pletely understood, the following synonyms had been used: cystic pseudotumor cerebri, meningitis serosa circumscripta, relapsing juvenile subdural haematoma, subarachnoid pouch, cerebral arachnoid cyst, chronic subarachnoid cyst and temporal lobe agenesis syndrome.The outward appearance of the patients is characterized by face and skull asymmetries with depression or elevation of the eyebrow; sometimes other