颅内炎性假瘤（IPT）是罕见的实体，经常导致恶性病变的误诊。识别这些病变很困难，但对于避免无意的医源性和调整治疗方案很重要。我们报告了一名 30 岁男性的病例，他出现单次强直阵挛性癫痫发作。脑成像显示右额叶病变具有轴内和轴外成分。根据放射学表现，怀疑患有脑肿瘤，因此患者接受了手术。病理检查得出浆细胞肉芽肿。全身CT扫描仅显示胸主动脉炎。完整的血液检查结果呈阴性。患者还接受了一系列抗体检测，其中抗核抗体呈阳性（血液水平高于 1/100）。脑脊液评估显示液体清澈，葡萄糖浓度正常，蛋白质水平正常，淋巴细胞增多。最后，IgG-4 血浆水平升高，导致 IgG4-RD 的诊断。该患者接受了泼尼松龙治疗，结果良好。IPT 有多种病因，其中 IgG4 相关疾病可能是鲜为人知的疾病之一，因为之前仅报道过 2 例病例。在此，我们报告一例新病例，一名年轻男子因 IgG4 相关疾病的颅内病变而出现癫痫发作。挑战在于怀疑此类情况以避免不必要的手术。© 作者。

Intracranial inflammatory pseudotumours (IPT) are rare entities that frequently lead to misdiagnosis with malignant lesions. The identification of these lesions is difficult, but important to avoid inadvertent iatrogenicity and to adjust therapeutic protocols.We report the case of a 30-year-old man who presented a single tonic-clonic seizure. Brain imaging showed a right frontal lesion with intra and extra axial components. Facing the radiologic presentation, a brain tumor was suspected, thus the patient underwent surgery. Pathological exam concluded to a plasma cell granuloma. A whole-body CT-scan showed only a thoracic aortitis. Complete blood work studies came back negative. The patient was also tested for an array of antibodies among which antinuclear antibodies were positive (blood level superior to 1/100). CSF evaluation revealed clear fluid with normal glucose concentration, normal protein levels and lymphocytic pleocytosis. Finally, IgG-4 plasma levels were elevated which led to the diagnosis of an IgG4-RD. The patient was put under prednisolone with a favorable outcome.IPT have several etiologies, among which IgG4 related disease may be one of the less known as only 2 cases have previously been reported. Herein, we report a new case of a young man who presented for seizures related to an intracranial lesion of an IgG4 related disease. The challenge is to suspect such conditions to avoid unnecessary surgeries.© The Author(s).