Aromatase Inhibitor-Associated Distal Radioulnar Joint Instability and Tear of the Extensor Digiti Minimi: A Case Report.

The addition of aromatase inhibitors has improved cancer-related outcomes in postmenopausal patients with estrogen receptor-positive breast cancer. However, aromatase inhibitor can be associated with a constellation of adverse musculoskeletal effects that comprises bone loss, arthralgia, myalgia, and tendinopathy. This medication complication, known as aromatase inhibitor-associated musculoskeletal syndrome, can limit treatment tolerability in many patients because of the high prevalence of aromatase inhibitor-associated musculoskeletal syndrome among those on aromatase inhibitor. The hand and wrist are the most affected joints in aromatase inhibitor-associated musculoskeletal syndrome, with patients presenting with symmetric arthralgia, stiffness, and tendinopathy. Radioulnar joint subluxation with extensor tendon tear has not been previously reported in patients with aromatase inhibitor-associated musculoskeletal syndrome. This is a case report of a 72-yr-old breast cancer survivor on an aromatase inhibitor presenting with chronic dominant wrist pain, weakness, and 5th digit finger drop. An extensor digitorum minimi tendon tear and radioulnar instability were identified using diagnostic musculoskeletal ultrasonography. This case illustrates the utility of in-office ultrasonography combined with dynamic examination for the often underrecognized pathology associated with aromatase inhibitor-associated musculoskeletal syndrome in breast cancer survivors.