Delayed Development of an Occult Pseudoaneurysm After Coiling of a Ruptured Anterior Communicating Artery Aneurysm

Aneurysm disappearance and reappearance is a rare condition, typically described in isolated case reports. We present a case of rebleeding following coiling of a ruptured anterior communicating artery aneurysm. To our knowledge, this is the first documented case of rebleeding due to the development of a pseudoaneurysm arising on the opposite wall of a coiled anterior communicating aneurysm, in which microsurgical clipping, coiling and flow diversion were all applied. The pseudoaneurysm demonstrated recanalization 1 week after surgical clipping, necessitating endovascular coiling. Subsequently, a flow diverter was deployed 8 days after coiling, following early recanalization at the pseudoaneurysm base. At 10 months, the follow-up angiography confirmed complete exclusion of both the pseudoaneurysm and the opposite wall aneurysm. This case illustrates the aggressive course of cerebral pseudoaneurysms, drawing the attention to the diagnostic and therapeutic challenges they present.