Male DCIS breast cancer treated with mastectomy and negative sentinel node

What happened, in summary

This 62-year-old man sought care because of pain and swelling behind the right nipple. Imaging of the right breast showed gynecomastia, a benign enlargement of male breast tissue, and no suspicious mass. The important cancer finding came from the opposite breast: magnified mammogram views of the left breast showed regional retroareolar microcalcifications extending toward the upper outer quadrant. Ultrasound did not find a matching mass, and the left axillary lymph nodes appeared normal, but the calcifications were suspicious enough to biopsy. A stereotactic core biopsy of the left breast showed grade II ductal carcinoma in situ, an early non-invasive breast cancer with intermediate nuclear features. Estrogen and progesterone receptors were positive. He was treated with left total mastectomy and sentinel lymph node biopsy. The sentinel node was negative, meaning no nodal spread was found. Final surgical pathology confirmed nuclear grade II DCIS, with all surgical margins uninvolved by DCIS. No invasive breast cancer, chemotherapy, radiation therapy, or endocrine therapy was described in the case text. The documented cancer course was therefore Stage 0 hormone receptor-positive male breast DCIS discovered during workup for symptoms on the other side, followed by definitive surgery with negative node evaluation and clear margins. The clinical story is most consistent with completed local treatment and survivorship after surgery, rather than metastatic disease or ongoing systemic treatment. The right-sided symptoms were therefore explained by gynecomastia, while the cancer was an incidental left-sided imaging finding. That distinction matters because the diagnostic workup separated benign male breast enlargement from true DCIS and led to treatment of the clinically silent breast abnormality before invasive disease or nodal spread was found.