Breast carcinoma in pregnancy with spheroid-like placental metastases-a case report.

Breast cancer is one of the most common malignancies diagnosed in pregnancy. Although the tumor is often detected at an advanced stage, placental metastases are rare. Here, we describe the case of a woman with breast cancer recurrence during pregnancy and subsequent metastases. The focus of this study is the large amount of placenta metastases, which have been analyzed immunohistochemically. Staining with trophoblast markers (placenta alkaline phosphatase, beta human chorionic gonadotropin and human placental lactogen) showed the strict localization of metastases in the intervillous space without invasion into fetal tissue. They have a large spheroidal shape and are free of blood vessels. Staining with Ki-67 revealed an outer proliferative shell and inner necrotic core. At week 28, a healthy newborn was born by elective cesarean section. A few weeks later, after surgery and FEC60 (fluorouracil, epirubicin, cyclophosphamide) cycles, the patient died. Breast cancer metastases in the placenta are rarely described. The special immunological environment in pregnancy may influence phenotype, growth, and behavior of tumor and metastases.