Two Similar Cases of a Misdiagnosed Anterior Communicating Aneurysm Rupture

The misdiagnosis of a ruptured aneurysm directly endangers patient's life and health due to the high risk of rebleeding and its sequelae. In this paper, we present two uncommon cases of anterior communicating artery aneurysm rupture with a relatively small intracerebral bleeding, seemingly without a diffuse subarachnoid hemorrhage (SAH), and a relatively mild clinical presentation. In these cases, the initial diagnosis failed, leading to missed aneurysmal ruptures. The atypical or mild clinical presentation, and the absence of SAH on computed tomography (CT) and/or magnetic resonance imaging (MRI) scan or absent blood in the cerebrospinal fluid (CSF) are all factors which could lead to a false or delayed diagnosis. Meticulous evaluation of patient's symptoms, CT, MRI scans, and CSF findings are mandatory. The possibility of a small blood clot without a diffuse SAH must be considered.