Cerebral tumour causing hydrocephalus with filling defect of the temporal horn.

The important diagnostic significance of filling defects of the temporal horn is well illustrated in the two cases here described. Both patients were middle-aged men with few neurological signs but with raised intracranial pressure and a moderate increase in cerebrospinal fluid cells and protein. In both cases the local cerebral symptomatology indicated a diencephalic disturbance. Ventriculograms showed extensive internal hydrocephalus with no significant lateral shift of midline structures but with filling defects and dislocation of the temporal horn. Although there was hydrocephalus, there was sufficient patency of the fluid pathways to permit the air introduced into the lateral ventricles to fill the fourth ventricle and cisterna magna. In Case 1 (Figs. 1, 2, 3) the deformity of the temporal horn is easily seen; in Case 2 (Figs. 7 and 8) it is minimal. Post-mortem examination in both cases revealed ependymoblastoma, which had deeply invaded the brain without causing much displacement. There were numerous secondary deposits throughout the walls of ventricular cavities, with the primary growth in relation to the left temporal horn in each instance, causing the filling defects. Some of the seedlings had caused partial obstruction of cerebrospinal fluid circulation. The deposits which caused obstruction were too small to have been detectable by pneumography.