Letrozole-Induced Sarcoid-Like Reaction Following Adjuvant Hormonal Therapy in Breast Cancer: A Case Report; هورمونی در سرطان پستان واکنش شبه سارکوئیدی القا شده با لتروزول پس از درمان کمکی Publisher



Sn Najafi Safa NAJAR ; N Najafi NIKI ; A Olfatbakhsh ASIIE ; H Hashemi HOWZHIN
Source: Iranian Journal of Breast Diseases Published:2025

Abstract

Introduction: Sarcoid-like reactions (SLRs) are rare, non-caseating granulomatous responses that may mimic metastatic disease in cancer patients. Although drug-induced SLRs are increasingly recognized, they remain underreported in patients receiving endocrine therapy for breast cancer. Case Presentation: A 49-year-old postmenopausal woman with hormone receptor-positive and HER2-positive invasive ductal carcinoma of the breast was treated with surgery, chemotherapy, radiotherapy, trastuzumab, and adjuvant letrozole. After 48 months of endocrine therapy, she presented with elevated CA 15-3 levels and imaging findings of a new pulmonary lesion with mediastinal lymphadenopathy, raising suspicion of recurrence. Diagnostic Assessment: Core needle biopsy revealed non-caseating granulomas, and positron emission tomography (PET)-CT showed no evidence of malignancy. Special stains excluded infectious etiologies. Intervention and Outcome: Letrozole was discontinued, and endocrine therapy was switched to Fulvestrant. Over 10 months, both the pulmonary lesion and lymphadenopathy resolved radiologically, and CA 15-3 levels normalized. Conclusion: This case highlights a rare instance of letrozole-induced SLR mimicking recurrence during breast cancer follow-up. Misinterpretation of such lesions may lead to unnecessary interventions. Clinicians should consider drug-induced etiologies when new lesions arise in asymptomatic patients on long-term hormonal therapy. © 2025 Elsevier B.V., All rights reserved.