2024 Volume 23 Issue 2 Pages 93-96
A 54-year-old woman was diagnosed with right breast cancer ten months prior to her rst visit to our department. Letrozole was administered orally for about nine months as preoperative therapy,followed by a right mastectomy. After resuming oral administration of letrozole as postoperative therapy, she developed edematous erythema and blisters primarily on her extremities 10 days later,prompting a referral to our department. Upon examination, the palpebral conjunctiva was congested, there was no pseudomembrane formation or corneal epithelial defect, and a slight fever of 37.3°C was observed. Histopathological examination of her skin indicated epidermal necrosis with subepidermal blisters. She was diagnosed with erythema multiforme major. Considering the possibility of a drug eruption caused by letrozole, we discontinued letrozole and started her on 55 mg of oral prednisolone daily (1mg/kg/day). The skin lesions resolved within three weeks. A druginduced lymphocyte stimulation test for letrozole, performed ve days after the initiation of oral prednisolone, was positive. Aromatase inhibitors, used as adjuvant therapy for breast cancer, block estrogen synthesis by inhibiting the nal step of the estrogen biosynthetic pathway. These inhibitors are classied into nonsteroidal and steroidal types, with letrozole being a nonsteroidal type. Letrozole was approved in Japan in 2006 as an aromatase inhibitor for the treatment of postmenopausal hormone receptor-positive breast cancer. Although a few cases of generalized eruptions that were treated with aromatase inhibitors have been reported, we herein report the present case with additional considerations, including the selection of alternative drugs. Skin Research, 23 : 93-96, 2024
