Lumbar Epidural Metastasis of Breast Cancer Resembling Lumbar Disc Herniation

A 49-year-old woman who had breast cancer suffered from left leg pain. Initial MRI indicated lumbar disc herniation compressing S1 nerve root. The pain was uncontrollable with conservative treatments and she underwent surgical decompression. Intraoperative findings showed that left S1 nerve root was compressed by soft and gray tumor locating ventrally. We resected the tumor and S1 nerve root was adequately decompressed. Bone tissue around the tumor was intact, and there was no finding of bone metastasis. Pathological examination demonstrated adenocarcinoma as same as original breast cancer. We should constantly consider differential diagnosis as metastatic lesion in case of malignancy.