title: Ruptured peripheral aneurysms in a collateral pathway associated with stenosis of a major cerebral artery: Report of two cases.
abstract: BACKGROUND
  While hemodynamic stress can result in aneurysm formation, it rarely contributes to the development of peripheral aneurysms in collateral pathways. We report two patients with ruptured distal aneurysms in a collateral pathway associated with stenosis of a major cerebral artery.
  
  
  METHODS
  A 67-year-old man presented with intracerebral hemorrhage in the right frontal lobe. Digital subtraction angiography (DSA) revealed severe stenosis of the right middle cerebral artery and two aneurysms in the collateral pathway of the right anterior cerebral artery. The ruptured aneurysm was trapped and resected; histologically, it was a true saccular aneurysm. The unruptured aneurysm was clipped and the patient was discharged without additional neurological deficits. The second patient was a 73-year-old woman with subarachnoid hemorrhage. DSA revealed three arterial dilations. On the 7(th) day of hospitalization, one of the aneurysms in a posterior inferior cerebellar artery-anterior inferior cerebellar artery anastomosis that functioned as a collateral pathway in the presence of severe basilar artery stenosis was found to be enlarged. It was treated by selective aneurysmal coil embolization with parent artery preservation. Her postoperative course was uneventful and she was discharged without any neurological deficits.
  
  
  CONCLUSIONS
  We document the successful treatment of two patients with ruptured aneurysms in the peripheral portion of a collateral pathway. We discuss the histology of peripheral aneurysms and present a review of the literature.
authors: Department of Neurosurgery, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori, Japan 030-8553.
authors: Ichiyo
authors: I
authors: Shibahara
authors: Shingo
authors: S
authors: Yonezawa
authors: Hiroki
authors: H
authors: Takazawa
authors: Tomohiro
authors: T
authors: Kawaguchi
authors: Masayuki
authors: M
authors: Kanamori
authors: Kensuke
authors: K
authors: Murakami
authors: Hiroshi
authors: H
authors: Midorikawa
authors: Tatsuya
authors: T
authors: Sasaki
authors: Michiharu
authors: M
authors: Nishijima