title: Pigmented villonodular synovitis of the hip presenting as a retroperitoneal mass.
abstract: We present an unusual case of diffuse pigmented villonodular synovitis (PVNS) of the hip presenting as a large retroperitoneal mass in an asymptomatic 39-year-old man. Initial imaging characteristics and findings on core needle biopsy suggested soft tissue sarcoma. However, incisional biopsy showed findings of PVNS. The patient underwent radical synovectomy and total joint replacement, with no change in the large retroperitoneal component after 15 months of follow-up.
authors.affiliation: Center for Diagnostic Imaging, 148 Second Street South, Waite Park, MN 56387, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Kallas
authors.forename: L
authors.initials: L
authors.lastname: Vaughan
authors.forename: P
authors.initials: P
authors.lastname: Haghighi
authors.forename: D
authors.initials: D
authors.lastname: Resnick
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip; D003937:Diagnosis, Differential; D006621:Hip Joint / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012186:Retroperitoneal Neoplasms / Q000175:diagnosis; D013586:Synovitis, Pigmented Villonodular / Q000175:diagnosis* / Q000473:pathology / Q000601:surgery; D014057:Tomography, X-Ray Computed