Teaching File Series

M R I - Division

Complaint : 36Y, Male c/o backache & pain in the lower limbs -  one year

FINDINGS:

 MRI :  Posterio-lateral extradural round cystic mass communicating with facet joint on Left side at L3/L4 level & causing   mass effect on thecal sac.

DIAGNOSIS:  Lt.L3/L4 Synovial facet cyst.

Differential Diagnosis :

Extruded disc fragment

• Not contiguous facet joint
• Usually anterior epidural
• Posterolateral uncommon
• Not as hyperintense on T2 WI

Ganglion cyst

• Likely from ligamentum flavum
• Difficult to distinguish by imaging
• Different pathologically
• Contains myxoid material
• Lined by fibrous connective tissue capsule

Nerve sheath tumor

• Intradural extramedullary most common
• “Dumbbell” lesion less common
• Intense post – contrast – enhancement

Septic facet arthritis

• Abscess extending out from facet joint
• Simulating synovial cyst
• Surrounding soft tissue edema and enhancement
• Adjacent marrow edema

Asymmetric ligamentum flavum hypertrophy

• Hypointense on T2Wi
• More broad-based contour
• Diffuse ligamentum flavum thickening/

REFERENCE : Jeffrey S. Ross,  Diagnostic Imaging, Spine 1st edition, 2004.

SUBMITTED BY:  DR. M.ADINARAYANA RAO. MD.

                              DR. D. PRASAD REDDY. DMRD.