Synchronous Unilateral Breast Cancer with HER2-Positive and TNBC Subtypes: Diagnostic and Therapeutic Challenges. A Case Report and Literature Review

Abstract Synchronous unilateral breast cancer presenting with different receptor subtypes are rare occurrences, with limited reports in the medical literature. Such cases pose unique diagnostic and therapeutic challenges. We present a case of a young patient initially diagnosed with a biopsy proven HER2-positive invasive ductal carcinoma, who was subsequently, upon further imaging, diagnosed with a second invasive ductal carcinoma with triple negative breast cancer in the same breast. This case underscores the significance of meticulous evaluation of the whole breast in the context of an existing carcinoma. Additionally, we emphasize the pivotal role of multidisciplinary teams, and review the current literature related to biology and treatment of such patients.