Breast carcinoma presenting as axillary metastases without evidence of a primary tumor

Sixty cases of axillary metastases from clinically occult breast cancer were analyzed. All cases had histologic evidence of metastatic nodes compatible with breast carcinoma.

Thirty-three patients underwent breast surgery at the time of histologic diagnosis of the axillary metastases, 6 patients were treated with radiation therapy to the breast, and 17 patients did not receive any immediate treatment of the breast carcinoma (9 of these subsequently had a primary breast carcinoma) during the follow-up. Thirty-seven of 60 patients underwent adjuvant therapy (29 underwent chemotherapy and 8 underwent tamoxifen therapy). From the histologic point of view, the number of metastatic nodes was 1 in 13 patients, 2 to 3 in 10 patients, and 4 or more in 23 patients; the number of metastatic nodes was not evaluable in 14 cases. Invasion was extranodal in 92% of cases. Eighty-six percent of cases were histologically classified as Grade 3 according to Bloom and Richardson.

The 5-year and 10-year survival rates were 77% and 58%, respectively. The comparison between the survival curves of the patients treated with immediate surgery/radiation therapy and of the patients whose cases were followed-up without treatment to the breast showed no difference. Adjuvant treatments did not improve prognoses.

The coexistence of a minimal (or unidentifiable) primary carcinoma with an extensive involvement of axillary nodes and a predominance of the undifferentiated histologic type, together with an unexpectedly good prognosis, makes this type of presentation an interesting example of a dissociated host resistance.