Age / Sex : 37 / M

Chief complaint: Left knee pain and swelling (remote onset, 5 years ago; recent onset, 1 month ago)

What is your impression?

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

(답안은 한 개만 보내주시기 바랍니다)

Courtesy: 김지나 (Kim Ji Na) 충남대학교병원 (Chungnam National University Hospital)

Intratendinous Gout

Discussion

Findings

Lateral radiograph of left knee shows swelling of the patellar tendon.

Axial T2-weighted images show high signal lesion with internal low signal foci within the patellar tendon. Diffuse thickening and contour bulging of patellar tendon is noted on sagittal FS T2-weighed image, T2-weighted image and T1-weighted image. T2 high signal intratendinous lesion with internal low signal tophi is shown within the patellar tendon. Nodular lesion with low signal intensity with adjacent subtle bone erosion is noted at the apex of the patella.

Diagnosis

Intratendinous Gout

Discussion

Gout is an inflammatory metabolic disorder characterized by raised levels of uric acid in the blood. It consists of a deposition of monosodium urate crystals (MSU), mostly in the joints or soft tissues. Achilles and patellar tendinitis are a relatively common clinical presentation of gout. Gout may lead to tendon rupture. US is a very useful diagnostic tool to assess intratendinous gout. They describe the appearance of gouty tophi as generally hyperechoic, heterogeneous, poorly defined masses, sometimes appearing as a cluster and surrounded by an anechoic halo. MRI shows tophi as structures of intermediate-to low-signal intensity and is therefore useful to confirm the diagnosis. CT scans can also be useful to diagnose gouty tophi.

References

J Clin Ultrasound. 2013 Mar-Apr;41(3):178-82

Ann Rheum Dis 1996;55:921-923

Orthopedics. Mar 11, 2011; 34(3): 223