Hematoma

Abscess

Disc herniations are most common ventral epidural mass in the spine

May have a thin rim of enhancement, especially if recurrent/post-operative

Most often associated with disc degeneration at that level

Thinning of articular cartilage, osteophyte formation

Often accompanied by ligamentous hypertrophy

“Blocky” facet morphology may be normal variant, not degenerative

Similar to facet arthropathy, often at a level with disc degeneration; may be a response to altered loading or instability

Posterolateral effacement of epidural fat and thecal sac

Post-traumatic, coagulopathic, or post-surgical etiology

Signal varies with age of hemorrhage

Mild or no peripheral enhancement

May be associated with disc space infection or instrumentation/inoculation

Marked peripheral enhancement typical

Thickened, calcified posterior longitudinal ligament

Ventral to thecal sac, may cause significant canal stenosis

Cervical involvement more frequent than thoracic

Best appreciated with CT

Enhancing soft tissue mass, may be multiple

Most often due to epidural extension of a vertebral metastasis, primary epidural metastases also occur

May also occur with transforaminal spread from a paraspinal or posterior mediastinal tumor