[Metastatic breast melanoma in a man: Case report].

Background: Malignant melanoma is a skin neoplasm that typically does not invade the breast, making its spread to the breast tissue in a male patient uncommon. When it metastasizes to the breast, it can present as a palpable mass or even be asymptomatic. Ultrasound allows for the detection of round hypoechoic lesions, while mammography detects well-defined nodules with increased density. The aim of this article is to describe the approach to a male patient with a breast mass and suspected melanoma, as well as the importance of immunohistochemistry for proper differentiation. Clinical Case: A 72-year-old male patient presented with a pigmented lesion on the sternum, an axillary tumor, and a right breast mass, which had been evolving for the past two years. He underwent resection, excisional biopsy, and simple mastectomy, respectively. superficial spreading melanoma with right breast metastases was documented. Immunohistochemistry supported the diagnosis, after positivity for HMB-45 and S100 was found in the examined samples. Conclusions: Metastatic melanoma in the male breast is an exceedingly rare finding. Immunohistochemistry plays a pivotal role in both diagnostic assessment and prognosis, as it guides treatment determination, which encompasses local and systemic interventions. For patients presenting as in this case, the optimal approach involves wide tumor resection with axillary lymph node dissection, coupled with adjuvant systemic therapy. Hence, case reporting is imperative to share diagnostic approaches in such patients and provide appropriate management strategies.