LAUSR

OBJECTIVE Aromatase inhibitors (AIs) are widely used in the adjuvant therapy setting in patients with estrogen receptor-positive breast cancer. Rheumatic side effects of AIs have been reported, including bone loss, arthralgias, myalgias, and tenosynovitis. There is emerging evidence that AIs are linked to new-onset autoimmune diseases. Here, we describe three novel cases of inflammatory myopathies that occurred during AI therapy. METHODS In total, three patients with inflammatory myopathy in the setting of AI therapy were treated in the Section of Rheumatology, MD Anderson Cancer Center. All the patients were retrospectively chart reviewed. We obtained verbal consent from the patients for use of their cases for teaching and publication purposes and only de-identified data have been used. RESULTS None of our patients from these three cases had a history of autoimmune disease and all had undergone recent cancer screenings, indicating no re-occurrence of breast cancer and no evidence of new cancer. The completion or discontinuation of AI therapy was associated with the resolution of the myopathies in all three cases. CONCLUSIONS This case series suggests a link between AIs and the new onset of inflammatory myopathy. If a patient develops an inflammatory myopathy while on an AI, the AI therapy should be considered the possible trigger. If the myopathy cannot be controlled with immunosuppression, then discontinuation of the AI should be considered.