Purpose or Case Report: Pediatric hepatic neoplasms include a variety of differentials which vary with the child’s age. We evaluated the diagnostic accuracy of certain imaging features on CECT in differentiating these tumors, particularly for identifying hepatoblastoma.
Methods & Materials: Two dedicated pediatric oncoradiologists performed a retrospective consensus review of CECTs of 147 children with treatment naïve liver tumors in this IRB-approved single centre study. Findings assessed include lobulated morphology, enhancement pattern, calcifications, central scar-like appearance, lobular arterial hyperenhancement, enhancing capsule, and metastases. Patient age, alpha fetoprotein (AFP) level, and hepatitis status were available at the time of review. Lesions were labeled as a particular pathology based on the imaging findings or labeled indeterminate. Diagnostic accuracy of CT was calculated, and the diagnostic performance of individual imaging features was analyzed.
Results: The median age was 1.5 years (range:1 month-15 years; 59% boys). 129/147 (88%) cases also had arterial phase imaging available. There were 116 (79%) hepatoblastomas, seven each HCC and rhabdoid tumors, six hemangiomas, five mesenchymal hamartomas, two angiosarcomas, and one each of embryonal sarcoma, FNH, adenoma, and epitheloid hemangioendothelioma. Counting indeterminates as inaccurate, the overall accuracy for diagnosis was 85%; it was 99.3% if indeterminates were excluded from the evaluation, with one hepatoblastoma misdiagnosed as rhabdoid tumor. Lobulated tumor morphology significantly correlated with hepatoblastoma (p <0.001), with specificity and PPV of 96.7% and 98.4% and an F1 score of 0.7. 22/25 cases that had a central scar were hepatoblastomas (96.5% specificity, 95.6% PPV, F1 score of 0.32). 31/32 cases with lobular pattern of arterial enhancement were hepatoblastoma (96.7% specificity, 96.8% PPV). Non-punctate calcifications were present in 58/147 (40%) cases including hepatoblastoma (n=51), HCC (n=4), hemangioma (n=2) and rhabdoid tumor (n=1), with an F1 score of 0.58. Three hepatoblastomas and one HCC had an enhancing capsule.
Conclusions: Imaging had a high diagnostic accuracy for pediatric hepatic tumors. Lobulated tumor morphology was significantly associated with the diagnosis of hepatoblastoma. Lobulated morphology, central scar-like appearance, and lobular arterial enhancement had >95% specificity and PPV in diagnosing hepatoblastoma.