表皮样囊肿起源于异位胚胎上皮细胞，是一种非常常见的良性颅内肿瘤。但脑室内表皮样囊肿的发生率较低，侧脑室内表皮样囊肿则更为罕见。在此，我们介绍一例侧脑室内表皮样囊肿的病例并复习相关文献。一名 54 岁女性主诉 5 年来反复头痛，最近 2 个月或更长时间症状加重。大脑计算机断层扫描显示侧脑室有低密度肿块，右心室扩大。头颅磁共振成像进一步证实该肿块为表皮样囊肿。该患者采用半球间开颅入路接受了显微手术切除结合内窥镜检查。肿块被顺利切除，患者恢复良好。侧脑室内表皮样囊肿常因侵犯周围脑组织或阻塞脑脊液系统而出现临床症状。诊断依靠磁共振成像检查，治疗依靠手术切除。患者的预后大多良好，取决于肿瘤是否切除干净。

Epidermoid cysts originate from ectopic embryonic epithelial cells and are a very common type of benign intracranial tumor. However, the incidence of intraventricular epidermoid cysts is low, and lateral intraventricular epidermoid cysts are even rarer. Here, we present a case of lateral intraventricular epidermoid cyst and review the relevant literature. A 54-year-old female complained of recurrent headaches over a 5-year period, with aggravated symptoms during the last 2 months or more. A computed tomography of the brain showed a low-density mass in the lateral ventricle and enlargement of the right ventricle. Cranial magnetic resonance imaging further confirmed that the mass was an epidermoid cyst. The patient underwent microscopic surgical resection combined with endoscopy using an interhemispheric craniotomy approach. The mass was satisfactorily removed, and the patient recovered well. Lateral intraventricular epidermoid cysts often present with clinical symptoms due to the invasion of surrounding brain tissue or blockage of the cerebrospinal fluid system. Diagnosis relies on examination by magnetic resonance imaging, and treatment relies on surgical resection. The prognoses of patients are mostly excellent and depend on whether the tumor is resected cleanly or not.