Primary breast diffuse large B cell lymphoma:a clinicopathologic study of twelve cases

Objective:To investigate the clinicopathologic features,immunohistochemical foundings and prognosis ofprimarybreast diffuse large B cell lymphoma(DLBCL).Methods:Twelve cases of primary breast DLBCL,diagnosed according to the 2008 World Health Organization staging standards for haematopoietic and lymphoid tumors,were retrospectively studied.Immunochemical study was perfomed and follow-up information analyzed.The histopathologic and immunophenotypic features of all cases were summarized.Subclassification was carried out when CD10 and/or Bcl 6 positivity and negativity for MUM1 were considered indicative of germinal center B cell like type DLBCL(GCB DLBCL)and the opposite expression as non germinal center B cell like subtype(non GCB DLBCL).Results:Female 10 patients,male 2 patients.Median age of patients was 49 years.7 patients in right breast,5 patients in left.12(100%)patients in stageⅠE.The International Prognostic Index(IPI)of 1 patients was 2,which of 2 patients was 1,and which of 9 patients was 0.Follow-up information was available in 6 patients(50%),four of which were still alive and two died(survived 7 and 19 months respectively).The patients usually presented with unilateral painless enlargement of breast.Morphologically,the lymphoma cells of 7 DLBCL cases showed a centroblastic variant,5 a immunoblastic variant.5 patients with lymphoepithelial lesions(LEL).Expression of Bcl6 and MUM1 protein was observed in 8 and 12 cases,respectively,and without expression of CD10 in 12 cases.All of 12 patients with DLBCL belong to the non GCB DLBCL.Most cases demonstrated high proliferation index,the median of Ki-67 index was 40%and more than 40%was found in 7 cases(58.3%).Conclusion:Primarybreast diffuse large B cell lymphoma is a rare entity,and shows a non germinal center B cell phenotype,accurate pathologic diagnosis relies on detailed histologic examination and immunochemical study,and treated mainly by chemotherapy combining with other therapies.