Atypical presentation of Gout masquerading as a Soft tissue Sarcoma

Introduction: Gout is a disorder of purine metabolism manifested by high serum uric acid levels, recurrent attacks of acute arthritis and deposition of monosodium urate crystals within and around the joints. Peri articular nodules are a challenge to both clinicians and diagnosticians especially if the nodules are large. Case presentation: A 34 year old male patient presented to the orthopedic clinic with a large localized progressive swelling in the region of the first Metatarsophalangeal joint of foot. Magnetic resonance imaging (MRI) revealed a large well-marginated lobulated, diffuse soft mass lesion around the 1st Metatarsophalangeal joint with encasement of surrounding tendons. The differential diagnoses given were synovial sarcoma, giant cell tumor and Pigmented Villonodular synovitis. Excision biopsy was done and histopathology revealed a classical picture of gouty tophus. Subsequently blood chemistry was done and showed marked hyperuricemia (7.8mg/dl). Conclusion: We present a case of gouty tophus masquerading as a soft tissue sarcoma. This case report serves to bring about awareness of an uncommon presentation of a common disease. Extraordinary presentations of gout, in its severe form can mimic a soft tissue tumor.