The case of a 39 year old III gravid, I parous woman is reported. Four years ago she had had breast cancer (T2N1MO). Three years later she suffered from recurrence and a tumor was removed from the right axilla. One year later she became pregnant and presented with multiple bone metastases in her 5th month of pregnancy. During the following time an obvious progression could be shown. Therefore, a caesarean section with ovariectomy was performed at the beginning of 29th week of gestation. Postoperatively the patient had a partial remission. It is argued, that this could have been caused by the interaction of pregnancy and malignant disease, especially by the influence of growth-promoting estrogens.
