title: Masses in the extensor mechanism of the knee: an unusual presentation of gout.
abstract: Tophaceous gout presenting as a soft tissue mass in an unusual location can pose a diagnostic challenge for radiologists. Tophi sometimes occur in a variety of unusual anatomic locations making them difficult to distinguish from tumors such as sarcomas. We report two cases of gout in the extensor mechanism of the knee, with imaging findings that were initially concerning for a neoplasm. One mass occurred in the patellar tendon and the other mass involved the quadriceps tendon. Both lesions had enigmatic imaging findings and to arrive at a definitive diagnosis, incisional biopsies were performed.
authors.affiliation: Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Jabour
authors.affiliation: Division of Orthopaedic Surgery, Dept of Surgery, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Karim
authors.initials: K
authors.lastname: Masrouha
authors.affiliation: Dept of Pathology ,University of Iowa Hospitals and Clinics, Iowa City, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Gailey
authors.affiliation: Musculoskeletal Radiology Section-Dept of Radiology, University of Iowa Hospitals and Clinics, Iowa City, USA.
authors.forename: Georges Y
authors.initials: GY
authors.lastname: El-Khoury
mesh_terms: D000368:Aged; D015210:Arthritis, Gouty / Q000175:diagnosis* / Q000473:pathology; D001706:Biopsy; D003937:Diagnosis, Differential; D005260:Female; D015743:Giant Cells, Foreign-Body / Q000473:pathology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007719:Knee Joint / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017847:Patellar Ligament / Q000473:pathology; D052097:Quadriceps Muscle / Q000473:pathology; D052256:Tendinopathy / Q000175:diagnosis / Q000473:pathology; D013710:Tendons / Q000473:pathology