title: Necrotic pseudotumor caused by a metal-on-metal total hip prosthesis: imaging characteristics on (18)F-FDG PET/CT and correlative imaging.
abstract: Necrotic pseudotumor is a complication of metal-on-metal arthroplasty that has been reported with increasing frequency in the last 5 years. It is believed to be the result of a hypersensitivity reaction to metal ions such as nickel, cobalt, or chromium that are released in large quantities from these prostheses. The imaging appearance of a necrotic pseudotumor caused by a metal-on-metal prosthesis, on (18)F-FDG PET/CT or (99m)Tc-MDP bone scan has not been previously described in the literature. Our case demonstrates that a necrotic pseudotumor can be detected incidentally in oncologic patients referred for an (18)F-FDG PET/CT or a (99m)Tc-MDP bone scan, and recognizing this process is vital in preventing further tissue necrosis and patient morbidity, as the offending prosthesis must be promptly removed. The imaging characteristics of a necrotic pseudotumor on PET/CT and bone scan may also mimic a malignant process such as a necrotic sarcoma, and can represent a potential pitfall leading to a false positive diagnosis in an oncologic patient.
authors.affiliation: Department of Nuclear Medicine, Brandon Regional Health Centre, 150 McTavish Ave E, Brandon, MB, R7A 2B3, Canada. makisw79@yahoo.com
authors.forename: William
authors.initials: W
authors.lastname: Makis
authors.forename: Christopher
authors.initials: C
authors.lastname: Rush
authors.forename: Gad
authors.initials: G
authors.lastname: Abikhzer
mesh_terms: D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005549:Foreign-Body Reaction / Q000000981:diagnostic imaging*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008670:Metals; D009336:Necrosis; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D008670:Metals; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D013669:Technetium Tc 99m Medronate