2026 年 13 巻 p. 485-491
Brain abscess developing at the site of intracerebral hemorrhage has rarely been reported. We report herein a case of brain abscess following intracerebral hemorrhage that mimicked a chronic encapsulated intracerebral hematoma. An 80-year-old man presented with right hemiparesis caused by a left frontoparietal subcortical intracerebral hemorrhage, which was managed conservatively. During hospitalization, progressive motor aphasia developed. Two weeks after admission, magnetic resonance imaging demonstrated worsening perihematomal edema and ring enhancement along the hematoma margin. Diffusion-weighted imaging demonstrated hyperintensity with heterogeneous restricted diffusion on the apparent diffusion coefficient map. Because there were no systemic signs of infection, chronic encapsulated intracerebral hematoma was initially suspected. However, the neurological and radiological deterioration progressed, prompting neuroendoscopic evacuation of the hematoma cavity. Microbiological examination revealed Enterococcus faecalis within the cavity, confirming the diagnosis of brain abscess. Targeted antimicrobial therapy led to clinical improvement. The possibility of a secondary brain abscess should be considered if delayed-onset neurological deterioration and worsening perihematomal edema are observed after intracerebral hemorrhage even in the absence of systemic signs of infection or typical diffusion restriction. Early microbiological evaluation of the hematoma cavity is essential to establish the diagnosis and determine the optimal treatment.
