Segmental duplications of the basilar artery, previously reported exclusively as anatomical variations, owe their clinical interest to the possible association with aneurysms localized at the junctions of the fenestrated segments. The morphological characteristics of 5 cases of basilar artery segmental duplication without aneurysms, found at autopsy, are reported. In 3 of these the proximal junction of the fenestrated segment was studied with scanning electron microscopy and morphometry. In all cases the tunica media of the medial wall of the 2 branches showed a progressive thinning towards the junctions of the fenestrated segments and a small muscular gap at their apex. The limited medial defect might be embryologically ascribed to the persistence of the morphological individuality of the tunica media of the 2 branches at the point where the fusion of the primitive longitudinal neural arteries stopped. The review of the literature shows that the morphology of the junctions of the fenestrated segments is in conformity with that of the intracranial arterial bifurcations. For this reason the basilar artery fenestration exposes to the blood flow a new distal bifurcation where the same etiologic factors that are still under discussion in the origin of saccular intracranial aneurysms may be active.

Aged↗

PubMedDate not supplied

Metastasis to intracranial meningioma as first clinical manifestation of occult primary lung carcinoma.

Metastasis to an intracranial meningioma was the first clinical manifestation of an occult primary bronchogenic carcinoma. The principles of diagnosis on morphologic and immunohistochemical findings are discussed, particularly as regards the differential diagnosis between a metastasis to meningioma and microcystic or secretory meningioma.

Humans↗

PubMedDate not supplied

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.

Arteriosclerosis↗

PubMedDate not supplied

Middle cerebral artery thrombosis following blunt head trauma.

Stroke caused by occlusion of an intracranial artery following blunt head trauma is a rare event. Traumatic dissections of the middle cerebral artery have been reported while thrombosis is very rare. We describe a case of fatal thrombosis of the left middle cerebral artery that occurred in the time interval between 2 and 6 hours after an apparently minor head trauma in a motor vehicle accident. The 25-year-old woman was in normal health on admission to the hospital. Two hours later the patient manifested nystagmus and vomiting. Six hours later she was aphasic with right hemiparesis. Twenty-four hours later the patient was comatose. A third CT scan performed at that time showed a wide infarct of the left cerebral hemisphere and a hyperdense left middle cerebral artery. The patient died 5 days after the collision. The autopsy confirmed the presence of the cerebral infarct and revealed thrombosis of the left middle cerebral artery. Microscopically, the transverse rupture of the intima and of the elastic lamina along the whole circumference of the vessel was found at the beginning of the thrombosed tract. We conclude that the blunt head trauma caused a partial rupture of the wall of the left middle cerebral artery with consequent thrombosis of the vessel and cerebral infarct. Based on the anatomy of the middle cerebral artery and on the review of the morphological literature we propose that the 2 types of lesion, the dissection and the thrombosis, that may follow closed head trauma, might depend on a common denominator that is the primitive rupture of the intima and elastic lamina.

Adult↗