Signet-ring cell carcinoma of the breast: a clinicopathologic study of 24 cases.

Twenty-four cases of signet-ring cell carcinoma of the breast are presented. These represented 4.5% of 535 cases of surgically treated breast cancer at Indiana University Medical Center. Twelve cases were associated with ductal carcinoma, nine with lobular carcinoma, one with colloid carcinoma, and four were pure signet-ring cell carcinoma. The mortality rate, incidence of axillary lymph nodal metastases, and number of involved lymph nodes were greater in cases of signet-ring cell carcinoma than with other forms of mammary carcinomas without signet-ring cells. It is proposed that signet-ring cell carcinoma can manifest as a pure lesion or as a variant of ductal, lobular, or colloid carcinoma, and that it is an aggressive histologic variant of mammary carcinoma.