Foreign Body Granulomatous Reaction of the Breast Mimicking Carcinoma: A Radiologic-Pathologic Diagnostic Pitfall.

Foreign body granulomatous reactions of the breast are uncommon benign entities that may closely mimic carcinoma on imaging. We report the case of a woman in her seventies who presented with persistent breast pain and an enlarging lesion detected on imaging. Mammography demonstrated architectural distortion and focal asymmetry, while ultrasound revealed an irregular hypoechoic mass with posterior acoustic shadowing, leading to classification as a Breast Imaging-Reporting and Data System (BI-RADS) 4 suspicious lesion. Ultrasound-guided core needle biopsy showed fibrous breast tissue with foreign body granulomatous inflammation and vacuolated spaces consistent with exogenous material, with no evidence of malignancy. Radiologic-pathologic correlation confirmed concordant benign findings, and surgical excision was avoided. The patient was managed conservatively with imaging surveillance and remained clinically stable on follow-up. This case highlights an important diagnostic pitfall in breast imaging and emphasizes the role of multidisciplinary radiologic-pathologic concordance in guiding appropriate management and preventing unnecessary surgical intervention.