Letrozole-induced inflammatory arthritis and tendinopathy in pediatric rheumatology setting

Musculoskeletal symptoms associated with the use of aromatase inhibitors are a well-known side effect of these drugs and are more prevalent in postmenopausal women. Aromatase inhibitor-associated symptoms are not overt inflammatory processes so are described as arthralgia syndrome. In contrast, aromatase inhibitor-associated inflammatory conditions such as myopathies, vasculitis, and rheumatoid arthritis were also reported. To our knowledge, inflammatory arthritis or tendinopathy associated with aromatase inhibitors were not reported in children despite their increased off-label use in the pediatric setting. Herein, we report a girl with inflammatory arthritis and tendinopathy associated with letrozole treatment.