Multiple myeloma presenting with amyloid arthropathy as the first manifestation: Two case reports

BACKGROUND: Multiple myeloma (MM) can be accompanied by amyloidosis, which occurs in a small number of patients and is characterized by deposition of light chains in the joints, leading to multiple myeloma-associated amyloid arthropathy (MAA). As a rare complication of MM, clinical manifestations of MAA are often similar to those of rheumatoid arthritis, and the two are easily confused. CASE SUMMARY: In recent years, our center treated two patients of MM with amyloid arthropathy as the first manifestation, both of whom presented with polyarthritis. After treatment for MM, both patients achieved complete remission. However, subsequently, the two patients underwent hip arthroplasty for femoral neck fractures. Congo red staining and immunofluorescence of the joint tissues confirmed MAA after surgery. Eventually, one of the patients died of MM recurrence, while the other survived. CONCLUSION: MAA should be regarded as an initial symptom of MM and should be taken seriously.