Malignancy metastatic to the products of conception: a case report with literature review.

Breast cancer is rare in adolescent females. Breast cancer metastatic to the products of conception is equally uncommon. We describe a 15-year-old girl who at 30 weeks of gestation was diagnosed with metastatic adenocarcinoma of probable breast origin. The placenta showed extensive intervillous disease. Metastatic disease within the intervillous space indicates hematogenous dissemination of cancer and a poor prognosis for the mother. The infant is almost always free of maternal disease unless there is villous invasion. Hormonal changes or immunotolerance by the mother may be involved in the pathogenesis. All placentas in which maternal malignancy is known or suspected should be examined grossly and microscopically.