Berry  Aneurysm

Most common locations of Berry Aneurysms:

·         Anterior cerebral artery (anterior communicating artery)

·         Middle cerebral artery

·         Internal carotid artery

Associated systemic conditions for Berry Aneurysms:

·         ADPCKD

·         Ehlers-Danlos syndrome (type IV)

·         Neurofibromatosis type 1

·         Marfan syndrome

·         Coarctation of aorta

·         Fibromuscular dysplasia of extracranial arteries

Predisposing factors for Berry Aneurysms:

-   Cigarette smoking and hypertension are

Berry Aneurysm Gross Features

Unruptured aneurysms are a thin-walled arterial outpouchings at branch points of the circle of Willis or a major vessel just beyond. Measure 2-3 mm and are shiny, bright red surface with thin, translucent wall. Atheromatous plaques, thrombosis, or calcification may be found in wall or lumen of aneurysm. Brownish discolouration of brain/meninges indicates previous hemorrhage. Rupture occurs at apex of sac with extravasation of blood to subarachnoid space, substance of brain, or both.

Histological Features of Berry Aneurysms:

Arterial wall adjacent to aneurysm shows intimal thickening and attenuation of media as it approaches the neck of the aneurysm. At the neck of the aneurysm the muscular wall and intimal elastic lamina stop short and are absent from the aneurysmal wall itself. The sac is made up of thickened, hyalinised intima. The adventitia covering the sac is continuous with that of the parent artery

References:

Robbins Basic Pathology 7th ed, edited by Vinay Kumar, Ramzi S. Cotran, and Stanley J. Robbins, 873 pp, Philadelphia, Pa, Sounders, 2003.