RESUMO
BACKGROUND: A 33-year-old renal transplant recipient presented with painless swelling of the right knee. Physical examination revealed an impressive knee joint effusion with no signs of inflammation. The patient did not remember a recent trauma, but he mentioned a strain 3 years earlier; radiographic findings had been normal at that time. The patient had suffered from end-stage renal disease due to chronic glomerulonephritis and had previously undergone two transplantations. At presentation, his kidney function was stable under treatment with ciclosporin, azathioprine and steroids. INVESTIGATIONS: Conventional radiography revealed a tumor at the superolateral pole of the right patella. Extensive soft tissue invasion and bone destruction was seen on MRI. A knee arthroscopy with biopsy, performed to aid diagnosis, showed extensive chondrocalcinosis macroscopically; histologically, gouty tophi were found. DIAGNOSIS: Pseudotumor of gout in the patella. MANAGEMENT: Uric-acid-lowering therapy with benzbromarone was started immediately after diagnosis. A local arthroscopic debridement of the right knee joint was performed 4 months later, and the patient remained asymptomatic for the next 3 years.
