Reference

1) Duguid, J. B.: Thrombosis as a factor in the pathogenesis of aortic atherosclerosis. J. Path. Bact. 60: 57-61, 1948. 2) Hojo, K., et al.: Juvenile bilateral carotid artery occlusion -a histopathologic study of the vascular changes-. & Nerve, in press. 3) Kawakita, Y., et al.: Spontaneous thrombosis of the internal carotid artery in children. Folia Pschy. Neurol. Jap. 19: 245-255, 1965. 4) Kudo, T.: Occlusion of the circle of Willis; a discussion on the developing process. Brain & Nerve 18: 889-896, 1966. S) Suzuki, J., et al.: The disease showing the abnormal vascular net-work at the base of brain, particularly found in Japan. II. A follow-up study. Brain & Nerve 18: 897-908, 1966.

Explanation of Photographs

Photo. 1. Left carotid arteriogram. Marked stenosis of the distal part of the internal carotid. Note an unusual anastomosis between the anterior cerebral artery and a branch of the external carotid, as well as a peculiar picture of fine vascular network at the base of the brain. Photo. 2. Left carotid artery. Marked luminal narrowing due to massive intimal thick- ening, consisting of fibrous connective tissue with myxomatous and edematous swelling. The internal elastic membrane is considerably well-preserved but partly calcified (to the right of this picture). Elastica-van Gieson. Photo. 3. Left middle cerebral artery. The lumen is occluded almost completely with myxomatous fibro-cellular thickening of the intima; the media is atrophic and the internal elastic membrane is somewhat tortuous and irregularly thickened. H.E. Photo. 4. A large number of arteriolar cross-sections, found over the pia-arachnoid membrane of the right Sylvian sulcus. H.E.

D-22. An Case of Cerebral Softening with Abnormal Vascular Network in the Cerebral Basal Region

Keiichiro AKACand Shigeo HASHIMOTO Department of Pathology, School of Medicine, Nihon University

Nobuo MORIYASUand Shu Nlsxlo Department of Neurosurgery, School of Medicine, Nihon University

This is a case of 55 year-old female who has repeated attacks of unconscious- ness in the past. Angiomatous net-like vascular abnormality was recognized at the carotid gabel by angiography on the both sides. The clinical course extended 4 years. Autopsy findings were as follows: Visceral organs: Heart weighing 230 gm. (Pulmonary ostia measuring 4.7

-274- cm. Aorta at its beginning measuring 4.5 cm.). There were noticed pyeloneph- ritis, cystitis and pulmonary edema in areas. Central nervous system: Brain weighing 1200 gm., the leptomeninges show- ing slight turbidity. There were noticed granular atrophy of the cortex predominat- ing bilateral frontal lobes and old large subarachnoid hemorrhage in areas along the Rolando's fissure. On cut surface the brain softening involved lenticula, and internal capsule in the left. The cerebellum and pons were seen in atrophy with disappearance of the left pyramidal tract. The changes of the Willis' circle were characterized by the following: 1) The location of the circle was within normal limit, but the vascular branches were essentially narrowed being comparable to that of the 3-4 year old of age. 2) The entire length of the bilateral anterior cerebral arteries, middle cerebral arteries (it. 5.0 cm. and rt. 2.0 cm.), bilateral posterior cerebral arteries (2.0 cm. each) were found string like in thickness and firm from their bifurcation points. The lumen of these arteries were almost ob- literated and filled with none blood. These transfered gradually into the normal appearing vessels. 3) In the vicinity of the string like arteries there were considerable numbers of blood vessels which anastomosed with each other and anterior choroidal arteries, posterior communicating arteries and anterior cerebral arteries. 4) Histologically the string like artery showed marked thinning of the wall conditioned by lacking media including muscles and elastic fibers. There was splitting of the internal elastic lamella which showed marked twist- ing to form wavy fold, neither nor inflammatory changes. Due to the focal thickening of the intima the lumen was markedly nar- rowed and filled up by loose reticular network of the fibrous tissue. 5) The vessels outside above arteries showed essentially normal pattern. As based on these findings, it seems reasonable to concluded that this case is caused by congenital vascular anomaly with aplasia or hypoplasia of the media in the Willis' circle.

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