There are several pathologic conditions which can be around the shunt catheter. But, reactive gliosis related to shunt catheter is uncommon. We report a case of reactive gliosis which has been suggested to catheter-related tumorous condition such as glioblastoma. The authors report a 45-year-old man who had a history of ventriculoperitoneal shunt placement for hydrocephalus after traumatic intracranial hemorrhage 10 years ago. General weakness and dementic mentality developed recently. MRI revealed multi-lobulating contoured dark signal lesion on T2 weighted image and MR spectroscopy suggest tumorous condition such as meningioma or lymphoma. The stereotacxic biposy was performed under navigation guide. Histopathologically, the specimen showed strong positive reaction on glial cells. There was no remarkable results on microbiologic study. After steroid medication, patient`s condition was improved and enhancing mass was subsided. There are several diseases related to shunt catheter that to be ruled out, we must note the possibility of reactive gliosis mimicking brain tumor, like this case.