We report the case of a 54-year-old woman presenting to our attention for a palpable breast lump. The mammographic examination showed multiple round/oval areas of increased opacity spread on both breasts. The ultrasonographic examination showed multiple hypo-anechoic nodularities without retro-tumor acoustic shadowing. The mammo/ultrasonographic findings were worthy of histological analysis, thus we performed a ultrasound (US)-guided core-biopsy, obtaining a histological diagnosis of neuroendocrine carcinoma, probably originating from the lungs. The subsequent whole body CT scan, performed to search the primary neoplasm, put in evidence a neoplasm in the left lung, involving the pulmonary hilum, and infiltrating the bronchial branches. Moreover, there were multiple secondary lesions involving adrenal glands, brain and bowel. A review of the literature confirmed that breast lumps may be the first manifestation of a metastatic disease.