Purpose or Case Report: Fetal MRI (FMR) has been particularly helpful in the evaluation of abnormalities observed on antenatal ultrasound (US). In this educational exhibit, the aim is to present the spectrum of liver abnormalities encountered in the fetus with US and FMR imaging. The most common entities encountered in utero include hemochromatosis, cystic lesions, hepatoblastoma, hemangioma, and metastatic disease. Antenatal identification of liver abnormalities contributes to accurate diagnosis and recognition of complications, ultimately guiding delivery, postnatal imaging, therapeutic planning, and treatment.
Methods & Materials: This retrospective analysis identifies fetal liver abnormalities from antenatal imaging studies of pregnant women at our tertiary care institution. These women were referred to the Perinatal Diagnostic Center for fetal abnormalities which include entities such as hemochromatosis, cystic lesions, hepatoblastoma, hemangioma, and metastatic disease. We identified key imaging findings of these fetal liver abnormalities present on US and FMR. Postnatal imaging is also presented as a correlate to the prenatal imaging findings.
Results: In fetuses with hemochromatosis, FMR demonstrates an abnormal hyperintense liver signal suggestive of iron overload. US of simple cysts reveals a hypoechoic well circumscribed mass and FMR reveals well-defined water-attenuated lesions without enhancement; T1-weighted scans reveal a low-intensity lesion while T2-weighted images reveal a high-intensity lesion. Hepatoblastoma presents on US as a heterogeneous mass with coarse calcifications and an osseous matrix; T2 weighted FMR images show a large, well-circumscribed heterogeneous mass lesion. Hepatic hemangioma appears as a focal well-demarcated mass of heterogeneous echogenicity and enlarged hepatic vessels; on FMR it presents as hepatomegaly with masses T2 hyperintense to the liver parenchyma. Neuroblastoma metastasizes most often to the liver in the fetus and neonate followed by leukemia and renal tumors.
Conclusions: US and FMR are valuable imaging modalities for characterizing various fetal liver abnormalities including hemochromatosis, cystic lesions, hepatoblastoma, hemangioma, and metastatic disease in the fetal liver. Management may be limited by the gestational age and maturity of the fetus but better knowledge of the appearance of these lesions can help guide delivery planning, postnatal therapeutic planning and may lead to improved neonatal outcomes.