Primary diagnosis of metastatic breast cancer in the third trimester of pregnancy: a case report and review of the literature.

To the best of our knowledge, we are presenting the first documented primary diagnosis of a 32-year-old pregnant patient at 29 + 4 weeks' gestation with poorly differentiated, metastatic scirrhous breast cancer, with negative hormone receptors, HER-2/neu receptor overexpression and metastases in the lumbar spine. The patient was administered neoadjuvant chemotherapy with vinorelbine and trastuzumab, and received ibandronate for the bone metastases. The tumor responded well to treatment; however, treatment was associated with anhydramnios, probably related to the trastuzumab treatment. Delivery was planned for 33 + 5 weeks' gestation by cesarean section due to concurrent breech presentation and anhydramnios, and the infant is in good health. After delivery, the patient underwent a mastectomy. Following completion of six courses of vinorelbine and ongoing treatment with trastuzumab and ibandronate, the patient's tumor went into regression and currently the patient does not present with any clinical evidence of disease.