Granulomatous systemic reaction mimicking sarcoidosis after hip arthroplasty: Diagnostic contribution of particle analysis.

INTRODUCTION

Sarcoidosis is the most frequent cause of systemic non-caseating granulomatosis in rheumatology. However, prosthesis-related granulomatous reactions induced by metallic particles can mimic sarcoidosis and should be considered in the differential diagnosis.

CASE REPORT: We report a 50-year-old woman with a right hip arthroplasty who developed acute bilateral granulomatous panuveitis. Laboratory tests excluded infection but showed systemic inflammation with elevated angiotensin-converting enzyme. PET scan revealed intense periprosthetic hypermetabolism and iliac lymphadenopathy. Lymph node biopsy demonstrated non-caseating epithelioid granulomas with multinucleated giant cells. Scanning electron microscopy with energy-dispersive X-ray spectrometry identified numerous metallic particles, mainly titanium and titanium-vanadium alloy, within granulomatous tissue. Blood titanium concentration was markedly elevated (138μg/L; normal<12). Explant analysis revealed a large wear trace at the femoral stem neck, explaining particle release. Prosthesis removal led to clinical improvement, with only mild recurrent uveitis controlled by topical corticosteroids. At one year, the patient remained clinically stable with partial remission on PET scan.

CONCLUSION

Prosthesis-related granulomatosis can mimic sarcoidosis. In patients with unexplained systemic granulomatous disease and arthroplasty history, particle analysis combined with implant expertise provides decisive diagnostic information.