Isolated Bicipito-radial Bursitis in a Patient With Rheumatoid Arthritis
A 78-year-old man had rheumatoid-factor and anti-CCP negative destructive rheumatoid arthritis for over 20 years. Medical treatment included methotrexate and etanercept and he had no signs of active inflammation. He presented with a large painless mass at the cubital side of his left elbow (Fig. 1). The elbow joint was not swollen and unrestricted in motion. There was no nerve involvement. A puncture yielded 25 mL of turbid fluid with a negative culture. After local injection with triamcinolone, the mass decreased but recurred thereafter. A plain X-ray of the elbow showed normal findings. MRI depicted a large bicipito-radial bursitis (white arrowheads pointing at the borders) with so-called “rice bodies” (black arrowheads) but without obvious connection with the elbow joint (Fig. 2). Most often a bicipito-radial bursitis is seen in case of synovitis of the elbow joint. It is akin to the popliteal cyst of the knee. The prevalence in rheumatoid arthritis is very rare. MRI imaging is the method of choice for establishing the diagnosis and differential diagnosis with other soft tissue tumors.