Abstract
A rare inflammatory breast disorder called lymphocytic mastitis is characterized by lymphocyte infiltrates in the mammary parenchyma. Due to their rarity, incidental observations of invasive ductal carcinoma in lymphocytic mastitis present diagnostic and management challenges. We present a case of a 52-year-old female with a history of painfully swollen breasts for three months who underwent a core needle biopsy, consistent with lymphocytic mastitis on histopathology. Due to persistent and worsening symptoms, a mastectomy was performed. During the examination, an incidental finding of infiltrating ductal carcinoma was identified in the mastectomy specimen. This unexpected discovery led to further investigations and altered the patient's treatment plan. The detection of invasive ductal carcinoma in the presence of lymphocytic mastitis highlights the importance of continuous surveillance and thorough examination. In the circumstances of lymphocytic mastitis, it is vital to take the likelihood of concurrent malignancy into account, especially when symptoms persist or reappear after appropriate management. This case report seeks to raise awareness among physicians of this exceptional association and drive further research that will explain its pathophysiology while enhancing management strategies.