Rheumatoid arthritis and aromatase inhibitors.

Aromatase inhibitors are widely used for the treatment of estrogen receptor-positive breast cancer in postmenopausal women. Joint pain is a common side effect. We report three cases of rheumatoid arthritis with onset after the initiation of aromatase inhibitor therapy. All three patients had antibodies to cyclic citrullinated peptides and two had sicca syndrome. Few similar cases have been published. Although a chance occurrence cannot be ruled out, evidence from animal models suggests that aromatase inhibitors may trigger or reveal rheumatoid arthritis.