Breast cancer (BC) in men represents between 0.5% and 1% of all BC diagnosed each year. We report a case of advanced BC in a 62-year-old male treated at our interdisciplinary Breast Cancer Center. The patient presented with a newly diagnosed large, symptomatic mass in his left breast. Clinical examination showed a not movable mass of 16 cm diameter, deforming the whole breast; the overlying skin was livid and hypervascularized. Enlarged lymph nodes were palpable in the axillary pit. He had no concomitant diseases at time of presentation. He denied any first- or second degree family medical history of cancer of any type and he never received radiotherapy. Ultrasound guided minimal-invasive 14-gauge core biopsy revealed a moderately differentiated encapsulated papillary carcinoma with high expression of estrogen and progesterone receptors (both > 80%, IRS 12) and HER2- negative. Because of the tumor size a mastectomy with axillary dissection and chest wall reconstruction using a latissimus dorsi flap was performed. Histological analysis showed invasive growth besides typical (non-invasive) papillary carcinoma and was classified as invasive solid papillary carcinoma; pT3 (10 cm), pN0 (0/15), M0, R0; OncotypeDX Recurrence Score indicated low risk (RS: 2). After discussion in the interdisciplinary tumor board meeting, radiation therapy and tamoxifen were recommended. The patient had an uneventful recovery and is disease-free after two years of follow-up. Male BC is typically diagnosed at an advanced stage, most likely due to a lack of awareness that men can develop BC. Therefore, in case of a large tumor, a flap-based thoracic reconstruction may be required.