Radiation therapy for primary breast lymphoma in male gynecomastia: a rare case report and review of the literature.

Primary breast lymphoma is a rare type of non-Hodgkin lymphoma and usually affects women, although a few cases have been reported in men. Chemotherapy and radiation therapy, or a combination of both, are frequently administered for treatment of primary breast lymphoma, as local control by surgical resection is poor. No standard therapy has been established, and the optimal radiation dose and irradiation field for male patients are unknown. The present report describes a 75-year-old man with bilateral cirrhosis-induced gynecomastia who was diagnosed with primary breast lymphoma; specifically, diffuse large B-cell lymphoma. Because of his hepatic dysfunction, he was treated with radiation therapy alone. Radiation therapy was followed by eight cycles of rituximab monotherapy. Clinical response was good, with no signs of relapse. Clinicians may benefit from knowledge regarding effective treatment of primary breast lymphoma in male patients, which has been rarely reported owing to the low incidence of this condition. The outcome in the present case may help to establish effective treatment guidelines in similar cases.