Hepatoblastoma with solid and multicystic aspect mimicking a mesenchymal hamartoma: imaging and anatomopathologic findings

A 29-day-old infant was evaluated at our center for a hepatic mass found during gestation. Ultrasound revealed a heterogeneous lesion which comprised three anechoic areas with hypoechoic debris and a predominantly hyperechoic central region with signs of vascularization on Doppler imaging (Figure 1A). Computed tomography showed a large bulging mass with three clearly defined cystic components with heterogeneous contrast enhancement of peripheral solid nodules (Figure 1B). The cystic component suggested a diagnosis of mesenchymal hamartoma. However , a highly elevated level of alpha-fetoprotein led to the diagnosis of hepatoblastoma, which tends to present as a solid lesion. An ultrasound-guided biopsy confirmed a mixed epithelial/mesenchy-mal hepatoblastoma (Figures 1C and 1D). Liver tumors are not uncommon in adults (1–4). Hepato-blastoma is the most common primary hepatic malignancy in children, accounting for nearly 80% of all malignant liver tumors (5). Hepatoblastoma usually presents as an incidental finding of an asymptomatic abdominal mass in children under 5 years of age. On ultrasound, hepatoblastomas appear as predominantly solid masses that are hyperechoic relative to the adjacent liver, although hypoechoic fibrotic septa can also be seen. Epithelial hepatoblastomas may appear homogeneous, whereas mixed epi-thelial/mesenchymal tumors are heterogeneous (due to osteoid, cartilaginous, and fibrous components) and frequently contain echogenic calcifications with acoustic shadowing and anechoic foci representing hemorrhage or necrosis (6). The appearance of hepatoblastoma on computed tomography is that of a well-defined mass with regular borders that is hypoattenuating in comparison with the adjacent hepatic parenchyma. The tumor commonly displays diffuse heterogeneous contrast enhancement. Approximately half of all hepatoblastomas appear lobulated or septated, especially on contrast-enhanced images (6,7). In the case presented here, the imaging findings indicated a different entity. The predominantly cystic appearance of the tumor was consistent with a cystic liver tumor, namely mesenchymal hamartoma. Mesenchymal hamartomas, which typically occur in children under 2 years of age, present as a large solitary neoplasm with variable amounts of solid and cystic components on ultra-sound or computed tomography (8,9). Our conclusion is that we should be aware of this rare mostly cystic presentation of hepato-blastoma, should we encounter cystic hepatic lesions in children under 3 years of age with elevated alpha-fetoprotein levels. embolization for unresectable symptomatic giant hepatic hemangiomas: single-center experience using a lipiodol-ethanol mixture. The role of gadoxetic acid as a paramagnetic contrast medium in the characterization and detection of focal liver lesions: a review. sarcoma with unusual features arising within mesenchymal hamartoma of the …