B-cell non-Hodgkin lymphoma of the breast in Waldenström's macroglobulinemia: a case report.

Background: Non-Hodgkin lymphoma (NHL) of the breast is a rare disease and can occur amongst patients affected by Waldenström's Macroglobulinemia (WM). WM is an indolent B-cell lymphoproliferative disorder with an overall incidence of about 1/100,000 in Europe. Breast imaging is not specific to breast lymphoma that often mimics benign lesions. The diagnosis is based on breast biopsy, the presence of MYD88L265P somatic mutation and immunoglobulin M (IgM) paraprotein detectable in the setting of lymphoplasmacytic infiltration by bone marrow (BM) biopsy. Case Description: A 60-year-old woman with personal and familial history of monoclonal gammopathy of undetermined significance (MGUS) and a lump in her right breast was referred to our hospital. Standard imaging showed round mass with smooth edges. The lump was biopsied and the pathology examination showed lymphoplasmacytic lymphoma (LPL) of the breast which led to final the diagnosis of WM. Conclusions: Lymphoma of the breast is a rare disease, often misdiagnosed because of the lack of specific features at mammogram and ultrasound. Core biopsy is crucial to make diagnosis of breast lymphoma and early diagnosis of WM has been shown to improve overall survival (OS). A comprehensive approach is required in order to assess patients affected by blood disorders presenting with a new breast mass that can lead to diagnosis of breast lymphoma.