A spontaneous dissecting posterior cerebral artery aneurysm in a one-year-old

We report a rare and complex condition in a one-year-old boy, where both an intracranial dissecting aneurysm and Factor XIII deficiency were present. The child was brought to the hospital due to spontaneous subarachnoid hemorrhage and an intracerebral hematoma in the occipital lobe. Magnetic resonance angiography revealed a ruptured dissecting aneurysm in the distal segment of the right posterior cerebral artery with PCA infarcts. The patient's neurological condition rapidly deteriorated due to a Factor XIII deficiency, which heightened the risk of bleeding. This was promptly managed with Factor XIII administration, stabilizing the patient sufficiently for arteriography, followed by successful coil embolization. For initial screening, CT angiography (CTA) or MR angiography (MRA) are effective, accessible options; however, cerebral angiography remains the gold standard for precise localization of cerebral aneurysms. This case highlights the critical role of timely diagnostic imaging and surgical intervention in managing pediatric intracranial aneurysms.