Lymphomas of the breast: primary and secondary involvement.

BACKGROUND: The involvement of the breast by lymphoma is a rare form of extralymph node lymphoma and represents either primary disease or systemic involvement. The authors hypothesized that screening mammography may influence the detection of lymphomatous involvement of the breast.
METHODS: All patients (n = 81 patients) who were diagnosed with lymphomatous involvement of the breast at the study institution between 1988 and 1999 were evaluated retrospectively.
RESULTS: Clinical information was available for 73 patients who could be classified into three major groups according to their diagnosis: primary breast lymphoma (PBL) (44%), breast involvement from disseminated disease at the time of initial diagnosis (29%), and recurrence of preexisting lymphoma to the breast (27%). The majority of PBL were of intermediate or high grade, and the majority of disseminated lymphomas involving the breast were of low grade. Lymphomatous recurrence to the breast was slightly more likely to be of intermediate grade rather than low grade. In 91% of patients, the diagnosis of lymphoma was made after the evaluation of a palpable mass. All patients who were identified after the evaluation of an abnormal screening mammogram (9%) had low-grade lymphomas. Of the 32 patients with PBL, screening mammography discovered only 1. Nineteen percent of patients with PBL also had a history of an autoimmune disorder.
CONCLUSIONS: These findings suggest that screening mammography has not altered substantially the detection of breast lymphoma. The clinical outcome of patients with breast lymphoma is dependent on histology and appears to parallel that of patients with lymphoma of similar histology involving other sites. Copyright 2002 American Cancer Society.