An intradural extramedullary metastasis to the spinal nerve root across dura mater is extremely rare. The authors encountered a case 39-year-old man who suffered radiculopathy arising from a soft mass around nerve root mimicking a nerve sheath tumor compressing the 4th lumbar nerve root in the right intervertebral foramen between the 4th and 5th lumbar spine. After an excisional biopsy, the metastatic infiltration of adenocarcinoma was confirmed pathologically. The primary lesion was found to be an intrahepatic cholangiocarcinoma with multiple metastases. This report suggests that an intradural metastatic tumor can show similar clinical and radiographic findings to other disease,s such as a nerve sheath tumor. The results also suggest that proper diagnosis and further treatment are possible only by pathological confirmation after and excisional biopsy.