Case Report: long-term survival of a male patient with breast cancer complicated by lung adenocarcinoma treated with individualized therapy

Male breast cancer (MBC) is a rare malignant tumor with unique clinical characteristics, accounting for only approximately 1% of all breast cancer cases. Although its pathological features are similar to those of female breast cancer (FBC), significant differences exist in the clinical manifestations, diagnosis, and prognosis of MBC. This article reports a case of a male patient with stage IV lung cancer complicated by invasive ductal carcinoma of the breast, which is extremely rare in MBC. The particularity of this case lies in the sequential occurrence of two malignant tumors, highlighting the importance of early identification of MBC to improve the overall prognosis of patients. Through detailed analysis of this case, we found that the potential pathogenic mechanism of MBC needs further investigation, and clinicians must maintain a high degree of vigilance when evaluating patients with existing malignant tumors to promptly identify potential coexisting tumors. We call for enhanced awareness of MBC in clinical practice to achieve early diagnosis and treatment, thereby improving patient survival rates.