Extranodal Lymphoma of the Breast.

Extranodal lymphoma represents fewer than 0.5% of all breast malignancies. Secondary involvement of the breast with lymphoma is more common than primary breast lymphoma. The most common primary breast lymphoma is B-cell lymphoma. The initial imaging study of choice for a woman with a new breast mass is a diagnostic mammogram. In younger women ultrasound is more commonly the first imaging modality performed. Diagnosis is made from image-guided or physical examination-directed needle biopsy. Treatment is different from that for breast cancer, in that surgery is not the mainstay. Patients with breast lymphoma are treated primarily with chemotherapy and radiation.