Lumbar Osteochondroma Arising From L4 Vertebral Lamina – A Cause of Radicular Pain.

Clinical history: Patient presented with history of radiating pain in the lower limbs and low backache. MR imaging finding: Exophytic bony outgrowth noted from the inner epidural surface of right lamina of L4 vertebra. The lesion encroaches on the spinal canal and right L5 lateral recess, impinging on the right traversing nerve root. The medullary cavity of the lesion is contiguous with that of the spinous process. Asymmetric diffuse disc bulge to left with left foraminal encroachment is noted at L4-L5. The disc encroaches on the left lateral recess. Canal stenosis is noted at this level; both traversing nerve roots are compressed and left exiting nerve root is indented.