A 43-year-old Japanese woman with adult T-cell leukemia (ATL) developed rheumatoid arthritis-like polyarthritis with dermatitis and skin erosion. Her rheumatoid factor and C-reactive protein results were positive. Musculoskeletal ultrasonography showed intra-articular and peritendinous power Doppler signal-positive synovitis. Plain magnetic resonance imaging showed synovitis of the above lesion and remarkable bone marrow edema/osteitis. She was diagnosed as having ATL-associated arthritis based on the invasion of ATL cells by skin biopsy at the arthritis lesion.
Keywords: Adult T-cell leukemia; Bone marrow edema; Human T-cell leukemia virus type 1; Magnetic resonance imaging; Synovitis; Ultrasonography.