Metastatic malignant melanoma of the breast: report of a case and review of the literature.

Melanoma is the most rapidly increasing cancer in the world. Associated morbidity and mortality are mainly related to metastatic potential. Metastases to the breast from malignant melanoma are rare and represent only 1.3%-2.7% of reported cases. The aim of this study was to present a rare case of metastatic malignant melanoma to the breast. A 51-year-old woman was admitted for management of a palpable mass of the left breast. The past medical history referred to a sizable nodular melanoma that was removed from her back. Classification of the breast lesion was BI-RADS 5. Core needle biopsy was compatible with the diagnosis of malignant melanoma. Immunohistochemical evaluation was positive for Mart1 and Ki67. Subsequent staging was indicative of multiple secondary foci in the liver and bones. The patient was administered a combination of PD L1 inhibitor nivolumab with the anti-CTLA4 inhibitor ipilimumab followed by additional targeted therapy with the BRAF inhibitor vemurafenib. Metastasis to the breast from malignant melanoma is extremely rare. Nevertheless, breast metastases must be suspected in patients with a history of malignant melanoma. Moreover, recent breakthroughs in the Braf and MEK inhibitors and immune checkpoint inhibition therapies have impressively improved prognosis in patients affected by melanoma.