Magnetic resonance imaging and computed tomography findings of hepatoblastoma in pediatric patients

Background / Objective Hepatoblastoma (HB) is the most common primary malignant liver tumor for children under 5 years old. Diagnosis involves alpha-fetoprotein (AFP), imaging modalities, and histological examination. High AFP levels are found in 80-90 % of patients. Magnetic resonance imaging (MRI) is preferred as it is radiation-free and differentiates soft tissues effectively, while computer tomography (CT) has rapid scanning speed and high spatial resolution. Early detection is crucial, and imaging is indispensable. Imaging techniques play a key role in HB staging, deciding on treatment, monitoring the effectiveness of treatment, and identifying any recurrences. We aim to identify HB's MRI and CT radiological diagnostic features in pediatric patients. Methods A retrospective analysis of three pediatric patients with radiologically and histologically confirmed HB was performed. Data from physical examination and AFP levels were collected. Imaging findings from MRI and CT scans were reviewed. By analyzing MRI and CT imaging modalities, characteristic patterns of HB were identified. Results We present three pediatric cases: a ten-month-old, a two-year-old female, and a three-year-old male. Palpable abdominal masses and a heterogeneous mass in the right hepatic lobe in the US were found in all cases. Elevated AFP levels varied from 10089 to 332000 kU/l. In all cases, a diagnostic liver biopsy confirmed the epithelial type of HB. MRI detected large, heterogeneous, lobulated masses measuring 12x8x9 cm in the second case and 12x9x12 cm in the third case, accumulating contrast and displacing adjacent organs with heterogeneous hypotensive T1w, hypertensive T2w signal intensity, and DWI restriction in two cases. Hemorrhage, small cysts within the mass, and heterogeneous enhancement in postcontrast images were seen in a ten-month-old case. A chest MRI detected multiple diffuse lung metastases in a two-year-old girl. In the male case, the primary benign hepatic tumor measuring 11x10x7 cm diagnosis was later revised to HB. CT scan detected a heterogeneous nodule in the right lobe with multiple satellite tumor nodules. Also, a contrast washout was seen. Conclusions HB is often large due to rapid growth and late symptom onset. On MRI, HB appears hypointense on T1w and hyperintense on T2w images. On CT, HB appears as a hypoattenuating lesion, followed by contrast washout. Hemorrhage and necrosis contribute to heterogeneous appearance. MRI and CT define vascular anatomy and tumor invasion.