Synchronous and Metachronous Metastatic Breast Cancer, with Different Histology and Opposite Immunophenotype, Treated with Combination of Chemotherapy, Anti-Her2, and Endocrine Therapy: A Case Report.

In the case of our patient, the synergic action of endocrine therapy and chemotherapy plus dual anti-HER2 combination allowed a complete disease control. Therapy should be scheduled by considering the two cancers as individual entities. The approach to breast cancer is changing from being considered a singular disease to a multiform one, according to current research focused on biological markers such as HER2, ERs, and PRs, with important implications in clinical, prognostic, and therapeutic features.