[Primary diffuse large B-cell lymphoma of the breast in a male patient with Sjögren's syndrome].

When a 74-year-old male patient visited our hospital for the treatment of herpes zoster, his computed tomography (CT) revealed a mass in his right breast, axillary lymph node enlargement, and multiple lung nodules. A histological examination of the breast and lymph node biopsies revealed diffuse large B-cell lymphoma (DLBCL) while the bronchial and salivary gland biopsies showed secondary amyloidosis and Sjögren's syndrome (SjS). According to the Ann Arbor staging, the clinical stage of the lymphoma was evaluated as IIE. The patient achieved a complete remission after six cycles of rituximab, pirarubicin, cyclophosphamide, vincristine, and prednisolone (R-THP-COP) combined with intrathecal chemotherapy to prevent meningeal infiltration and irradiation after chemotherapy. Primary breast lymphoma was diagnosed within 2% of the breast tumor. Only sixteen male cases of breast lymphoma have been previously reported. In those reports, gynecomastia and hormonal therapy accounted for nine cases, but none of the cases coexisted with SjS. The present case is suggestive of the need to investigate possible autoimmune involvement in the development of lymphoma.