OBJECTIVE: Malignant melanomas presenting with unknown primaries are uncommon. In the majority of cases metastases of occult melanoma were detected in skin or in lymph nodes. Melanoma can rarely occur as a primary or metastatic intramammary tumor. CASE REPORT: We report the case of a 58-year-old Caucasian woman who came to our department with a voluminous mass in her right breast. Histopathological examination found metastasis of epithelioid melanoma with unknown primary lesion. Our patient underwent a radical enlarged mastectomy, but due to the extension a radical removal was not possible. DISCUSSION: In 2.2% of cases, melanoma may present with a metastasis without an identifiable primary lesion; this case should be considered a stage IV melanoma (Tx; N1; M1) due to the extension of the lesion and the infiltration of adjacent structures. CONCLUSIONS: In literature, the presence of a breast metastasis of melanoma with unknown primary origin was reported just in one case. The execution of histopathological analysis is mandatory for a correct differential diagnosis with primary carcinoma of the breast. Palliative metastasectomy should be discussed with multidisciplinary melanoma board.