Bilateral Primary Breast Cancer: A Case of Synchronous Diagnosis and Management of Ductal Carcinoma <i>In Situ</i> and Invasive Ductal Carcinoma

<b>Aims/Background</b> Bilateral breast cancer (BBC) is an uncommon subtype of breast cancer which occurs either synchronously or metachronously. Synchronous BBC with distinct histological types in the left and right breasts is particularly rare. <b>Case Presentation</b> This report presents a case of a 57-year-old female patient diagnosed with bilateral primary breast cancer, characterized by ductal carcinoma <i>in situ</i> (DCIS) in one breast and invasive ductal carcinoma (IDC) in the other. The patient initially sought medical attention due to a palpable mass and pain in her left breast, leading to a diagnosis confirmed through imaging studies and biopsy. The patient was treated with three cycles of neoadjuvant therapy, followed by a modified radical mastectomy on the left breast and a lumpectomy on the right breast. Postoperatively, the patient received endocrine therapy and radiotherapy, with no evidence of recurrence observed to date. <b>Conclusion</b> Further research and clinical advancements are necessary to optimize treatment and care strategies for patients with bilateral breast cancer, ensuring that their unique therapeutic needs are effectively addressed.