Tophi gout around the knee joint: An unusual presentation with a soft tissue mass

Abstract

Introduction: Gout is the most common inflammatory arthropathy. It has been reported to affect 2.13% of population in the United states. In this report, we presented an uncommon case of tophaceous gout of the knee presenting as a soft tissue mass. case report: A 57-year-old male patient with knee pain and localized progressive swelling increasing in time on the medial side of the proximal tibia was seen in our clinic. He did not have any rheumatologic disease known previously except gout arthritis. Excisional biopsy was performed by preserving medial collateral ligament and histopathologic investigations were done next. A tophaceous gouty deposit was identified by low-power photomicrograph. A bluish amorphous material was seen surrounded by bundles of dense collagenized tissue and chronic inflammatory cells. surrounding the amorphous crystalline deposit is a thin layer of mononuclear and giant cells. Photomicrograph of another section has been stained by de Galantha's method for demonstration of monosodium urate crystals. conclusion: Especially in patients with extra-articular or subcutaneus mass, tophaceous gout must be considered as differential diagnosis.