Idiopathic Granulomatous Mastitis in a Postmenopausal Woman Mimicking Breast Carcinoma: A Diagnostic Challenge.

Idiopathic granulomatous mastitis is a rare benign inflammatory condition of the breast characterized by granulomatous inflammation affecting the lobular units. Clinically, it most commonly presents as a palpable breast mass with pain, erythema, or skin thickening, and may be accompanied by abscess formation or fistula development. Because these findings overlap significantly with those of breast carcinoma, the disease frequently poses a diagnostic challenge for clinicians. We report a case of idiopathic granulomatous mastitis in a postmenopausal, 55-year-old patient presenting with extensive inflammatory breast disease and imaging findings highly suspicious for malignancy. Core needle biopsy was negative, showing a discrepancy with the highly suspicious imaging and clinical characteristics, which led to operative management with lumpectomy.