Intracranial metastasis via transplacental (vertical) transmission of maternal small cell lung cancer to fetus: CT and MRI findings.

We present the computed tomography (CT) and magnetic resonance imaging (MRI) findings of brain metastases in an unusual case of a premature, 33-week gestational age neonate who was emergently delivered from a mother suspected of having lung cancer according to imaging performed during the third trimester of pregnancy. Owing to the presence of placental metastases noted after delivery, the fetus had initial screening with brain MRI and chest/abdomen CT as well as serial screening imaging studies during the first 5 months of life, all of which were apparently normal. However, serial examinations eventually revealed a cerebellar lesion that significantly improved after chemotherapy but recurred and enlarged within a few months. This lesion was later confirmed to be metastasis by subsequent biopsy and resection. More metastatic lesions were identified in the frontal and temporal lobes on follow-up MRI. In the setting of aggressive maternal malignancy (without known fetal primary malignancy) an intracranial mass can, on the exceedingly rare occasion, result from maternal high-grade malignancy and the neuroradiologist should be alerted to this phenomenon.