[Primary breast diffuse large B-cell lymphoma in an elderly man maintaining long-term complete response]

Primary breast diffuse large B-cell lymphoma (DLBCL) is a rare non-Hodgkin's lymphoma that mostly affects women. Here, we report a case of primary breast DLBCL that affected an older man without any autoimmune disease or drug-related female hormones. The patient was a 65-year-old man whose chief complaints were gradually-increasing lump in the right chest and swelling of the right axillary lymph nodes. He was diagnosed with malignant lymphoma through a needle biopsy on suspicion of right breast cancer with right axillary lymph node metastasis. Since the histological type could not be confirmed, right breast mass resection was performed. The patient was referred to our department for treatment because of the diagnoses of primary breast DLBCL, germinal center B-cell type (Hans classification), and clinical stage IIA. In addition to the six courses of R-CHOP therapy, intrathecal injections were used in combination to prevent CNS infiltration. He has been in complete remission for 5 years. Although rare, breast lymphoma can also occur in men; therefore, early histological diagnosis and response to CNS recurrence prevention are important.