A Case Report of Erythema Nodosum Following Letrozole Administration in a 44-Year-Old Iranian Female Patient with Breast Cancer

Letrozole, a nonsteroidal aromatase inhibitor, is the adjuvant endocrine treatment for postmenopausal women with estrogen receptor-positive breast cancer. Erythema nodosum (EN) is a rare skin adverse effect of letrozole which has been previously reported in a few case reports. We report a new case of EN-induced by letrozole in a 63-year-old Iranian woman with left breast cancer who was estrogen receptor-positive. Physical examination and laboratory findings were consistent with EN. Manifestations resolved following discontinuation of letrozole and treatment with oral prednisolone. This case highlights EN as a potential adverse effect of letrozole. Clinicians should be aware of this rare but significant reaction, as early recognition and discontinuation of the offending agent can lead to complete resolution of symptoms