Primary malignant lymphoma of the breast. With a review of 73 cases among Japanese subjects.

We report a case of a 71-year-old female with primary malignant lymphoma of the breast. The patient noticed a lump in the right breast approximately six years prior to consultation to the Surgical Department because of a rapid growth of the lump, and had no other tumors noticed throughout the body during that period. Histology proved the case to be a "reticulum cell sarcoma" (large cell type) producing IgM in the tumor cells, instead of a breast carcinoma as clinically diagnosed. At the same time, a total of 73 cases of mammary malignant lymphoma among Japanese subjects were reviewed. The criteria for primary or secondary malignant lymphoma of the breast, and histological diagnosis and pathogenesis of the primary breast malignant lymphoma were discussed.