1. A 26-year-old man was first seen in September 1961. From childhood he had suffered from right-sided headaches, mainly in the temporal region and below the eyebrow, the pain being treated as migraine. As time went on, the headache ceased to trouble him, but he then began to complain of attacks of vertigo, associated with nausea or vomiting, usually lasting about one hour and being so severe that they forced him to go to bed for fear of falling. It was for these attacks that he sought advice. The neurological examination and funduscopy at that time were normal. Skull films and tomograms revealed a hyperostosis in the left fronto-parietal region, growing from the outer table, with a circular defect, limited sharply by sclerotic bone. In the tangential view there was thickening of the inner table in the base of the hyperostosis. These appearances were suggestive of a meningioma, and angiography was undertaken with this possibility in mind
2. Total serial angiography confirmed these circulatory anomalies. The patient refused surgical treatment, as he did not consider that his complaints were troublesome enough at this time. He was readmitted on 2 February 1964 because the headaches had recurred, and because he had had several attacks of transient weakness of the right hand, and on two occasions loss of consciousness. The neurological state remained normal
3. At operation on 25 February 1964 a right occipitoparietal craniotomy was performed. On the surface of the brain an anomalous vein, as large as a thumb, ran from the occipital to the parietal lobe, forming a large varix just before its termination in the sagittal sinus. The arachnoid was thickened over the whole of this region. From all directions large arteries entered the vein so that a thrill could be felt on palpation. When all these arteries had been ligated, the tension in the vein
4. For some days after the operation the patient was somnolent and confused and had a left-sided hemiparesis. This complication cleared up rapidly, but a superficial wound infection required antibiotic therapy for several days. He was discharged in good mental and physical condition. Control angiography was carried out on 1 April 1964 (Fig. 4a, b, c, d). The cerebral circulation in both hemispheres now appeared to bevirtually normal. All of the main cerebral arteries on the right side had diminished in size and the arteriovenous communications were no longer visible. Both of the carotid arteries were smaller and irregularly narrowed, but there was an aneurysmal dilatation of the origin of the posterior communicating artery on the left side
5. This vascular anomaly is unique in its form, and in the literature no similar observation could be found. It is the nearest to the one described by Dandy (1945), but in comparison is more complicated and larger. In Haberland's,1950