Percutaneous balloon kyphoplasty is an option for pain relief in pathological vertebral compression fractures. Complications related to cement leakage through cortical defects have been reported. On the other hand, dural compression due to retropulsion of the tumor mass is rarely reported. The authors report a case of a 65-year female patient who had cauda equina syndrome after a percutaneous balloon kyphoplasty in a pathological vertebral fracture, even though epidural compression were not found prior to surgery. Magnetic resonance imaging revealed retropulsion of the tumor mass into the spinal canal through the disrupted posterior vertebral cortex.