Metastasis of a breast carcinoma in a mature teratoma of the ovary.

Metastatic tumors in ovaries from breast carcinoma are well known. Breast carcinoma metastases in primary ovarian tumors are much more uncommon. The authors present a case of a primary breast carcinoma, with a lobular component (signet ring cells), which metastasized into a mature cystic teratoma of the ovary. The problem of differential diagnosis with other primary ovarian tumors or metastatic tumors and the problem of particular behavior of metastatic lobular components are discussed.