[Fornix and septal tumor (author's transl)].

This study attempts to supply to internists exact and specific references to succeed early to the diagnosis of "fornix and septal tumor' with or without callosal extension. After a short anatomical recall, a neurophysiological study of the fornix permits to the authors to explain about the physiology of the memory and to place the function of this commissural formation from the classic hippocampal and mammillian theory and from more recent fundamental ideas about the part of thalamus. The evocation of the function of corpus callosum in the harmony of the thought and movements shows many deep neuronal circuits necessary to a normal activity. These data emphasize the specific neuropsychological semiology of these tumors at the "incipiens' period before that appear the symptoms of intracranial hypertension or invading and adjoining structures. Thus, it is possible to describe a syndrom of the anterior middle line that is different of a frontal semiology appeared at a more late period. It is necessary to show the minor or neglected psycho-organic disorders and to scan by a neuropsychological searching examination. The specialized and complementary explorations have been, during a long time, difficult to explain. Still, the C.T. scanner reduces these difficulties and will be realize at the least doubt. In the Lille's neurosurgery department, we recall the importance of the deep phlebogram's study during the angiographic examination and we define diagnosis tests. The ventricular explorations are always good but more exact if a stereotactic methodology is used. This one permits to specify the mass due to a lesion, the histological constitution without forgetting its therapeutic action. These efforts, in the diagnosis approach, are justified by the anatomo-pathological study that proves the great percentage of benign tumors. The operative technics is clearly defined: surgical approach, essential structures reference, definition of the tumor's limits with tela choroïda and the third ventricle, surgical excision as complete as possible. The therapeutic results depend on the histology and extension of the tumor. Their benign composition during a long time and the inefficacy of the radiotherapy, except sometimes, plead in favour of a surgical treatment. This one is more easier that it is earlier.