Megalodolichobasilaris: the effect of atherosclerosis on a previously weakened arterial wall?
The morphological findings of 2 basilar artery giant fusiform aneurysms are presented. In one case (a 63-year-old man) the aneurysm was accidentally found at autopsy. Its wall was mainly formed by fibrous tissue without a smooth muscle layer and presented fragmented but still recognizable elastic lamina. In the media there were small well-formed bony spicules. In the other case (a 59-year-old man) the aneurysm had broken causing subarachnoid hemorrhage. The wall showed a marked reduction of smooth muscle cells and thinning and fragmentation of elastic lamina. A second sacciform aneurysm was present at the basilar tip. The review of the literature and the morphological findings of the 2 cases, characterized by abnormality of the portion of the basilar artery not directly involved in the aneurysm wall, consisting of a diffuse deficit of the tunica media and lamina elastica, might suggest that the fusiform aspect of the aneurysm may be the result of the degenerative effect of atherosclerosis on a cogenital, structural or dysmetabolic, or acquired, inflammatory, weakening of the arterial wall.
De Caro
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Institute of Human Anatomy, University of Padua, Italy.
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Munari
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D001161:Arteriosclerosis / Q000150:complications / Q000473:pathology*; D001488:Basilar Artery / Q000473:pathology*; D004730:Endothelium, Vascular / Q000473:pathology*; D006801:Humans; D002532:Intracranial Aneurysm / Q000209:etiology / Q000473:pathology*; D008297:Male; D008875:Middle Aged