Cerebral Herniation Caused by Post-irradiation Brain Abscess: A Report of Two Cases and a Systematic Review

Radiation-induced necrosis is commonly seen after radiotherapy for nasopharyngeal carcinoma (NPC), but a post-irradiation brain abscess is rarely encountered and easily overlooked, which may lead to a dismal outcome. We describe two Chinese men with cerebral herniation caused by temporal lobe abscess within a radio-necrotic lesion presenting only with headache and neurological defects. Cranial magnetic resonance imaging (MRI) or computed tomography (CT) showed cystic lesions in the temporal lobe with a severe mass effect. Both patients had brain herniation before emergency operations. Therefore, our findings suggest that a post-irradiation brain abscess may insidiously develop into disastrous herniation, and regular multi-modality neuroimaging follow-up should be carried out to help avoid this situation.