New primary ipsilateral metachronous breast tumor: a case report.

After breast-conserving treatment, the occurrence of ipsilateral breast tumor relapse raises the concern regarding whether it may represent two distinct types of lesion that it is important to define, a true recurrence (TR) or a new primary tumor (NPT). TR and NPT have different natural histories, prognosis, and in turn different implications for therapeutic management. We report the case of a 35-year-old woman who developed a breast invasive ductal carcinoma, which after receiving breast-conserving treatment with adjuvant chemotherapy, radiotherapy and hormone therapy, developed four years after an inflammatory carcinoma in the same breast, with different expression of immunohistochemical markers than the first breast cancer. The patient was treated with neoadjuvant chemotherapy that allowed the realization of a radical mastectomy with a complete pathological response. We describe the diagnostic and therapeutic approach of ipsilateral breast tumor relapses, along with a review of existing literature.