Distal anterior cerebral artery (DACA) aneurysms, also called pericallosal or A2 aneurysms, are rare and comprise about 1.5 to 9% of all intracranial aneurysms. In this study, a series of 10 patients with DACA aneurysms who were surgically treated in our clinic is presented and discussed, focusing on their clinical features and surgical outcomes.

A total of 344 patients with cerebral aneurysms were operated on in our clinic and 10 patients (2.9%) with DACA aneurysms were studied retrospectively. All patients underwent a computed tomography (CT) scan followed by four-vessel digital subtraction angiography (DSA).

Initial CT revealed intracerebral haematoma (ICH) in 7 patients (70%) and in 2 of them the haematoma was over 3 cm in diameter. The pericallosal-callosomarginal bifurcation was the most common location in 9 patients (90%). Four cases (40%) showed multiple aneurysms. The mean waiting time for the operation was 4.8 days. Surgical clipping was performed in all the cases. Multiple aneurysms required two different craniotomies in the same session. The patients with ICH over 3 cm in diameter, in addition to poor preoperative grade, are likely to have a poor outcome, and so clinical grade is the definite factor affecting the surgical outcome of patients.

DACA aneurysms are usually small and bleeding occurs irrespective of their size because of the lack of resistant arachnoid membranes at the level of the pericallosal cisterns. All DACA aneurysms, even if very small in size or discovered incidentally, should be aggressively treated because of the high tendency to rupture.