Learning Radiology xray montage

Pigmented Villonodular Synovitis

  • Benign synovial proliferation primarily affecting knees with erosions, cysts, soft tissue swelling but with preservation of the joint space, no osteoporosis or calcification. Pigment is hemosiderin

  • Clinical

    • Frequent history of antecedent trauma
    • Hemorrhagic "chocolate" effusion
    • Insidious onset of swelling
    • Pain of long duration
    • Decreased range of motion
    • Joint locking

  • Age

    • Mainly 2nd-4th decade; 50% <40 years
    • F>M

  • Location

    • Knee (most common)
    • Ankle
    • Hip
    • Elbow
    • Shoulder
    • Tarsal or carpal joints
    • Predominantly monarticular

  • Radiographic findings

    • Soft-tissue swelling around joint
      • From effusion and synovial proliferation
    • Dense soft-tissues from hemosiderin deposits
    • Subchondral pressure erosions at margins of joint from hypertrophied synovium
    • Multiple sites of deossification appearing as cysts
    • No calcifications
    • No osteoporosis
    • No joint space narrowing (until late)

pvns, pigmented villonodular synovitispvns, pigmented villonodular synovitis

AP and lateral views of the knee demonstrate marked soft tissue swelling,
cystic changes in both the femur and tibia without significant joint space narrowing

  • MRI findings

    • Masses of synovial tissue in a joint with effusion
    • Scalloping / truncation of prefemoral fat pad
    • Predominantly low signal intensity on all sequences (due to presence of iron) (characteristic of this lesion)
    • Often heterogeneous low + high signal intensity on T2WI (hemosiderin deposits in masses + para-articular fat)
    • DDx
      • Hemosiderin deposits in other diseases (eg, rheumatoid arthritis)

  • Treatment

    • Synovectomy
    • Arthrodesis
    • Arthroplasty
    • Radiation

  • DDx

    • Synovial sarcoma
      • Mass around, but outside of, joint
      • Frequently calcify
    • Degenerative arthritis
      • Joint space narrowing
      • Subchondral sclerosis