Mutism due to a massive hematoma after rebleeding of an aneurysmal subarachnoid hemorrhage in the territory of the distal anterior cerebral artery

Background: The mutism caused by hematoma after subarachnoid hemorrhage (SAH) is extremely rare, and the details of its clinical course have not been clarified. Case Description: A 75-year-old woman who presented with transient loss of consciousness and a subsequent severe headache was transferred to our hospital. She was diagnosed with the World Federation of Neurosurgical Societies Grade II SAH due to the rupture of an aneurysm at the A2–3 junction in the left anterior cerebral artery (ACA). Endovascular coil embolization was successfully performed; however, postoperative computed tomography (CT) confirmed a massive hematoma in the corpus callosum and expansion into the cingulate gyrus, which was suspected to be due to preoperative or intraoperative rebleeding. The patient remained completely mum, which was considered as mutism due to a hematoma in the ACA territory. The postoperative clinical course was favorable, and the patient had fully recovered speech fluency with the disappearance of hematoma on CT scan at 44 days after the occurrence of SAH. Conclusion: This is a rare case of mutism caused by an interhemispheric hematoma due to rebleeding after SAH. No radical evacuation of the hematoma may be desirable for the improvement of mutism because additional structural damage to the ACA territory by surgical stress should be avoided.