Imaging Case of The Week 77

The following ankle x-rays are from a 77 year old male with right ankle swelling and pain who has a history of hypertension. What can you see?

Right ankle 3

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Right ankle 1

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Right ankle 2

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[peekaboo_link name=”Answer”]Answer[/peekaboo_link] [peekaboo_content name=”Answer”]

The ankle x-rays show a well defined, punched out lucency on the medial aspect of the lateral malleolus with a sclerotic margin. The joint space is narrowed with osteophytic lipping and there is soft tissue swelling around the ankle joint.

The most likely diagnosis of the x-ray appearance is gout. This patient had elevated uric acid levels and a past history of gout. He was treated for acute attack of gout and responded well.

Ankle, gout

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Punched out lesion in gout is due to erosion from long standing soft tissue tophus. Gout deposits around the joint can be intra-articular, subchondral or juxta-articular.

In rheumatoid arthritis, which commonly involves small joints symmetrically, marginal bony erosions will not have sclerotic margins and there will be juxta-articular osteoporosis.