Placental metastasis from maternal bronchial oat cell carcinoma

We describe the case of a young pregnant woman with oat cell carcinoma diagnosed by immunohistochemical reactions and ultrastructural study of a mediastinal biopsy specimen. A neonate was delivered by a cesarean section without evidence of carcinoma, but a thorough pathologic examination of the placenta showed intervillous metastasis of the maternal oat cell carcinoma. This case is interesting, since placental metastases from solid tumors are rare (38 reported cases with pathologic examination of the placenta), and 39% of them arise from maternal melanomas.