MALIGNANT HEMATOPOIETIC BREAST-TUMORS

Hematopoietic neoplasms involving the breast, although less common tha n breast carcinoma, are often clinically indistinguishable from other breast tumors. Microscopically, these tumors can mimic primary carcino ma of the breast, especially in limited material such as needle biopsy specimens. Forty-five hematopoietic breast neoplasms including 21 pri mary non-Hodgkin's lymphomas (NHLs), 19 secondary NHLs, 1 undetermined NHL, 1 lesion secondary to Hodgkin's disease, and 3 granulocytic sarc omas were reviewed with regard to histologic subtype, morphologic feat ures, and immunophenotype. The median age of patients at presentation was 67 years for those with primary NHLs and 61 years for those with s econdary NHLs. The majority of lymphomas were intermediate or high gra de. Diffuse large cell type was by far the most common histologic subt ype. No lymphomas resembling lymphomas of mucosa-associated lymphoid t issue were identified in this series, suggesting that such lymphomas a re rare in breast compared with other sites such as the gastrointestin al tract and lung. Four primary NHLs, 2 secondary NHLs, and 1 granuloc ytic sarcoma were initially misdiagnosed as carcinomas; three patients underwent radical mastectomy, and at least three other patients nearl y received surgical treatment. One primary anaplastic large cell lymph oma of B-cell origin was identified that closely resembled poorly diff erentiated ductal carcinoma. ''Single file'' or targetoid patterns wit h extensive sclerosis mimicking invasive lobular carcinoma was common in lymphomas and was seen in one of the granulocytic sarcomas. In addi tion, two breast lymphomas, one of B-cell phenotype and the other of T -cell phenotype, showed frequent signer ring cells, which potentially could be confused with lobular carcinoma. Despite a number of recent a rticles on lymphomas of the breast it appears that these tumors contin ue to be confused with carcinomas. Histologic features suggestive of l ymphomatous involvement include absence of in situ carcinoma, frequent individual karyorrhectic cells, lymphoepithelial lesions, and cellula r discohesiveness.