Age / Sex : 31 / M

Age / Sex : 31 / M

Chief complaint : Both ankle pain

Gouty arthritis

Discussion

Findings:

1. X-ray

-  Tound, radiopaque soft tissue masses

-  Juxta-articular bony erosion

-  Bony proliferation and overhanging edges

2. MRI

- Juxta-atricular mass lesions (talocalcaneal, talonavicular)

       - PD : intermediate to low SI

       - T2 : intermediate to low SI

       - Enhancement : peripheral, heterogeneous enhancement

       - Bony erosion

- Relatively preserved joint space

- Soft tissue masses with bony erosion

Differential Diagnosis:

Non-neoplastic condition - Chronic tophaceous gout (monosodium urate)

Neoplastic condition – Xanthofibroma, Benign fibroblastic tumor

Diagnosis:  Gouty arthritis

Discussion:

Gout is a monosodium urate deposition disease, related with hyperuricemia. It is one of the most prevalent inflammatory arthropathies with a prevalence of approximately one point four percent. Gout displays a striking tendency to affect the foot, in particular the first metatarsophalangeal joint. The initial attack of gout affects the first MTP joint in about seventy percent, as monoarticular disease. However, mid-foot and ankle involvement without 1st MTP joint involvement can occur in twenty-five to fifty percent patients. According to the disease progress, oligo– and poly–articular involvement could be presented.

1. X-ray – (not advocating the use of MR imaging in the initial diagnostic evaluation, if the diagnosis is evident radiographically - clearly calcified tophus or typical erosions.)

 1) Soft tissue findings : Tophus, Calcific deposit in 50% tophi

 2) Joint findings : Preservation of joint space initially, Cartilage destruction in late, Abscess of periarticular demineralization

 3) Bone findings : ‘punched-out’ lytic bone lesion ± sclerosis of margin, Overhanging margin (40%)

2. MRI – (MRI appearance of gouty tophi is not pathognomic)

 1) T1W : intermediate homogenous SI

 2) T2W, other fluid-sensitive sequences : variable SI (m/c: intermediate to low T2 SI)

             - Variable calcium deposition

             - Usually, soft tissue tumor shows high T2 signal intensity. Thus, some aurthors proposed that relatively low T2 SI in the bone erosion related soft tissue mass could be a clue for imaging diagnosis of tophaceous gout.

 3) Enhancement : heterogeneously enhancing

             - d/t hypervascular synovium and granulation tissue surrounding tophi.

References:

Yu JS, Chung C, Recht M, Dailiana T, Jurdi R. MR imaging of tophaceous gout. AJR 1997;168:523-7