[Chondroma of the lumbar spinal canal: a case report].

Chondroma is a benign cartilaginous tumor and fairly rare in the spine. A case of chondroma in the lumbar spine is presented. A male at age 66 was suffered from progressive low back pain associated with hypesthesia in his right leg. Radiographic examination showed an extradural mass in the dorsal part of spinal canal at L 5 level. No osteolytic change was noted by CT scan. MRI showed iso-intensity with marginal enhancement on T 1-weighted images and heterogeneous intensity on T 2-weighted image. The mass was totally removed by laminectomy and pathohistologically diagnosed as chondroma. Postoperative course was uneventful and the symptoms disappeared completely. One of the origin of chondroma is thought to be metaplasia of the connective tissue in contact with spine. This is why no pathological change was found in bone adjacent to the tumor. Careful preoperative diagnosis and total removal of the tumor is important since malignant transformation may happen in chondroma.