A Case of Bilateral Trigger Thumbs Secondary to Aromatase Inhibitor

• The authors have no financial conflicts of interest. which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. A 49-year-old woman visited our department due to painful bilateral trigger thumbs, which were characteristically locked in flexion (Fig. 1A). Both thumbs showed passively correctable locking and the patient did not perform an extension of both thumbs because it was very painful. There were no palpable nodules in either thumb. The patient had no history of previous trauma or familial history. Laboratory tests were normal, including blood sugar, erythrocyte sedimentation rate, C-reactive protein, renal function, thyroid function, and rheumatoid factor. Radio-graphs of the hands were also normal. Three years ago, the patient underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy due to endometrial adenocarcinoma. One year later, treatment with pelvic radiotherapy and anastrozole (Arimidex ® , AstraZeneca, Seoul, Korea) was started due to iliac lymph nodes me-tastases. Since then, the patient experienced tolerable arthralgias, myalgia, and mild triggering during the treatment with anastrozole. After 2 years of treatment with anas-trozole, the patient developed severe triggering and locking in both thumbs. Conservative management with local steroid injections was not effective and further aggravated the triggering. We performed surgical intervention on both thumbs. During surgery, we found thickening of the A1 pulley of both thumbs, and the flexor pollicis longus tendon was caught at the A1 pulley. A1 pulleys of both thumbs were released and partial excised (Fig. 1B and C). Thereafter, the patient was able to actively move both thumbs, and complete relief of both locking thumbs was confirmed. The symptoms completely disappeared at one month after the surgery (Fig. 1D). Hyperestrogenism is an important risk factor for the development and progression of endometrial cancer. 1 Aromatase inhibitors (AIs) block the aromatase enzyme , which converts peripheral testosterone and androgens to estrogens, subsequently lowering estrogen-modulated stimulation. 1 Hence, AIs are useful in the management of endometrial cancer. However, musculoskeletal complaints, particularly arthralgia and myalgia, in patients treated with AIs have been reported. It has been suggested that AIs reduce the antinociceptive effects of estrogen by complete estrogen depletion, and therefore, decrease the pain-threshold, resulting in arthral-gia. 2 Also, it has been reported that AIs are associated with carpal tunnel syndrome (CTS) and trigger finger. CTS has been reported to be associated with all AIs, an-astrozole, exemestane, and letrozole.