[Chronic brain disease in old age-a case report contributing to the problem of differential diagnosis (author's transl)].

This is a report on the case history of a 66-year old female patient whose chronic involutional melancholia was disguised by the signs of a slowly growing clival meningioma with consecutive occlusional hydrocephalus. Despite repeated stays in hospital the deteriorating mental findings were wrongly diagnosed as an organic psychosyndrome of vascular origin until shortly before her death. Typical difficulties in differential diagnosis of the organic psychosyndrome in aged patients are discussed on the basis on the course taken by the disease in this particular case. This case also shows the fundamental possibility of neurosurgical treatment of cerebro-organic disturbances conditioned by disturbances of CSF circulation.