Age / Sex : 70 / F

Chief complaint: 

1) What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(Quiz는 quiz일 뿐이오니 답안은 한개만 보내주시기 바라오며, 복수의 답안을 보내주시는 분은 정답이 포함되어 있더라도 부득이 semi-correct answer로 처리토록 하겠습니다.)

Courtesy: 

CPPD disease (calcium pyrophosphate deposition disease), manifested as pseudogout at left ankle joint and lateral superficial bursitis

Discussion

Findings:

Plain radiography: osteophytes formation at left ankle joint.

                 Calcifications along joint space of left ankle joint.

                 Soft tissue swelling, lateral side of lateral malleolus.

Soft tissue calcifications.

CT: Capsular calcifications around left ankle joint.

Ligamentous calcifications at left ankle joint.

Soft tissue calcifications at lateral superficial bursa.

Subchondral cyst formation along tibiofibular joint.

MRI: thick and extensive synovitis at left ankle joint.

     Subchondral cyst formation along tibiofibular joint.

     Lateral superficial bursitis.

     Chondromalacia, medial portion of tibiotalar joint.

Differential Diagnosis: gout

Diagnosis: US-guided aspiration of effusion of left ankle joint and lateral superficial bursa

Discussion:

CPPD disease is a kind of crystal deposition disease, in which crystal (calcium pyrophosphate dehydrate) may be detectable anywhere including cartilage, synovium, capsule, tendon, bursa, ligament and vessel. Many patients are usually asymptomatic or have atypical pattern of osteoarritis, for example involving unusual non-weight bearing joint or excessive osteophytes. In some cases, patients may experience pseudogout attack, induced by trauma, intra-articular injection or other event. Radiologically, stippled articular or periarticular calcifications are apparent on plain radiographs or CT. Pyrophosphate arthropathy is a form of structural damage of joint, with joint space narrowing, bony sclerosis and cyst formations. In ankle, atypical location such as midfoot, talocalcaneal joint may be involved, different from osteoarthritis.

References: Bone and joint imaging 3^rd ed. Elsevier. P 459-73.