Myélome à chaînes légères révélé par une arthropathie amyloïde. À propos de deux observations

Amyloid arthropathy associated with multiple myeloma: a systematic analysis of 101 reported cases

OBJECTIVE

Amyloid deposition in multiple myeloma (MM) may lead to an arthropathy resembling rheumatoid arthritis (RA). Since a systematic description of its natural history is lacking, we have performed a systematic analysis of all published cases.

METHODS

Literature review featuring backward and forward database searches and direct inspection of reference lists. Inclusion criteria were as follows: publication between 1931 and 2012, diagnosis of multiple myeloma, and demonstration of light chain amyloid (AL) in any organ or in synovial fluid, arthritis, or synovitis.

RESULTS

Overall, 101 cases were identified. Median age was 59 years and the male-to-female ratio was 1:1. A systemic manifestation of MM was reported in 88 cases. In 53 of these, characteristic physical findings (carpal tunnel syndrome, macroglossia, shoulder pad, and soft tissue swelling/masses) were present. Arthritis manifested before the diagnosis of MM in 63 cases, with 33 cases initially misdiagnosed as RA. There were 72 cases of poly-, 17 of oligo-, and three of monoarthritis. The shoulder joint was most commonly affected, followed by knees and small hand joints. Median synovial fluid leukocyte count was 2460 cells/mm(3), and was normal in seven cases. Synovial histopathology often featured mild synovitis without plasma cell infiltration. Imaging revealed articular or periarticular inflammation in many cases and bone lesions near 22% of affected joints. Treatments varied but led to some improvement in the majority of cases.

CONCLUSIONS

These results solidify previous experience that MM arthropathy tends to feature a symmetric RF-negative nonerosive polyarthritis. However, the results also highlight the diversity of its presentations and stress the importance of arthropathy as a potentially under-recognized presenting manifestation of MM.

Amyloid arthropathy mimicking seronegative rheumatoid arthritis in multiple myeloma: case reports and review of the literature

We report two patients who suffered from symmetrical polyarthritis simulating rheumatoid arthritis. Acute phase response was almost within normal limits, and autoantibodies including rheumatoid factor were negative. Both of them were diagnosed as having amyloid arthropathy (AmyA) secondary to kappa multiple myeloma based on deposition of kappa-light chain-immunoreactive amyloid in biopsied tissue and Bence Jones protein in urine. Systemic AL amyloidosis may be important in the differential diagnosis of chronic polyarthralgia.

Multiple myeloma presented as acute interstitial nephritis and rheumatoid arthritis-like polyarthritis

Acute interstitial nephritis and rheumatoid arthritis (RA) or RA-like polyarthritis are among the very rare paraneoplastic manifestations of multiple myeloma (MM). A 47-year-old man with acute renal failure due to interstitial nephritis was admitted to our university hospital and successfully treated with corticosteroid. He later developed a symmetric distal polyarthritis with morning stiffness mimicking RA. On follow-up, the patient had a rise in serum creatinine, hypercalcemia, anemia, and a monoclonal spike (Bence Jones protein) on the urine protein electrophoresis. Bone marrow biopsy demonstrated a diffuse neoplastic plasma cell infiltration. Diagnosis of MM was made and the patient received chemotherapy. After four-course chemotherapy, the patient's articular manifestations resolved, urine monoclonal spike disappeared, and serum creatinine returned to a near normal level. We hypothesize that in this case, immunologic hypersensitivity reactions to the light-chain molecules or other tumoral antigens deposited within the kidney or joint spaces, in the context of MM cytokine milieu may have resulted in this unusual presentation. Ultimately, clinicians and pathologists should consider MM in the differential diagnosis of the acute interstitial nephritis and RA-like polyarthritis.