Maternal gastric adenocarcinoma with placental metastases: what is the fetal risk?

The incidence of maternal cancer during pregnancy is low, and metastatic disease involving the placenta is rare. We present a case of rapidly progressive and fatal gastric carcinoma presenting during pregnancy, with spread to the maternal blood space within the placenta but no chorionic villous invasion and no evidence of fetal transmission at the time of delivery or on 12-month follow up. To the best of our knowledge, there have been only 5 previous single case reports of gastric carcinoma metastatic to the placenta. This case highlights the need for clinical vigilance against dismissing gastrointestinal symptoms as pregnancy related and for pathologists to carefully examine the placenta in the setting of maternal malignancy. When placental metastases are present but with no villous invasion, the risk of fetal metastasis may be extremely low, even in the setting of aggressive, terminal malignancy in the mother.