Objective: Primary amyloidosis is classical in the course of multiple myeloma (MM), but peripheral amyloid arthropathy is unusual. We evaluated the frequency and effect of amyloid arthropathy in a single center series of patients with MM.
Methods: Retrospective analysis of cases of peripheral joint amyloidosis in a cohort of patients with MM.
Results: Between 1978 and 1996, 11 patients (6 women, 5 men, mean age 59 yrs) were diagnosed with biopsy proven amyloid arthropathy in a cohort of 311 patients with MM. Arthritis was the first symptom of amyloidosis in all patients and occurred within the 6 months after MM diagnosis in most patients (7/11). Nine patients had light chain MM and X light chain was more common than kappa (6 vs 5). Shoulder hypertrophic arthropathy and rheumatoid arthritis-like polyarthritis were the 2 most common involved sites. In most cases, joint involvement was responsible for major limitations in activities of daily living. Amyloid deposits were clearly visible on magnetic resonance images (MRI), which also showed inflammatory synovitis in some cases. Control of MM was often associated with improvement of amyloid arthropathy, but additional rheumatological treatment--oral low dose prednisone or joint steroid injection--was often needed to achieve more complete relief. Amyloid arthropathy was not associated with decreased survival, except for patients with concomitant cardiac involvement.
Conclusion: This series provides reliable information on amyloid arthropathy, especially regarding functional effects, anatomical lesions on MRI, and therapeutic options.