Thrombotic Aneurysm of Posterior Inferior Cerebellar Artery

Spontaneous thrombosis of an intracranial aneurysm is rare but is common in fusiform or large cystic aneurysms, which result in subarachnoid hemorrhage after rupture. This case reports a 47-year-old woman with subarachnoid hemorrhage who developed spontaneous thrombosis of an aneurysm due to rupture of the posterior inferior cerebellar aneurysm.

The patient was admitted to the hospital with history of sudden headache and vomiting for 3 days. According to early imaging findings, she was initially diagnosed as having a cavernous hemangioma with hemorrhage in the left cerebellum, but according to the intraoperative pictures and postoperative pathologic results, the diagnosis was an aneurysm with thrombosis.

This case represents a rare but important complication of ruptured intracranial aneurysm, which can be easily misdiagnosed or ignored. It should be given great attention and considered in patients with subarachnoid hemorrhage who are negative for imaging examinations.