A 73 years-old woman presented with locally advanced breast cancer (cT4b cN1 M0, stage IIIB) and atrial flutter. Because of the arrhythmia, chemotherapy or tamoxifen, although malignancy was hormone-sensitive, were discarded. Letrozole was started. Two months later, the breast nodule and skin ulceration cleared up. Surgery was performed. Nowadays, 24 months later, patient does fine, continuing letrozole as adjuvant treatment.