Imaging Features of Hepatocellular Carcinoma in Children With and Without Underlying Risk Factors.

Pediatric hepatocellular carcinoma (HCC) is an aggressive malignancy for which imaging findings remain poorly described. In comparison with adult HCC, pediatric HCC more commonly occurs without underlying risk factors, and standardized surveillance guidelines for those with predispositions are lacking. The purpose of this article was to evaluate imaging findings of nonfibrolamellar pediatric HCC and to identify associations between these imaging findings and the presence of predisposing factors. This retrospective study included children (≤ 18 years) with histologically confirmed nonfibrolamellar HCC who underwent multiphase CT or MRI at one of four academic children's hospitals between July 2009 and April 2019. Surveillance regimens in children with predispositions were at the discretion of treating physicians. Clinical characteristics were recorded. Scan indications were classified as surveillance versus clinical signs and symptoms. Images from all sites were submitted to a cloud-based server. Two radiologists independently assessed imaging features of HCC, including tumor size, tumor in vein, Pre-Treatment Extent of Tumor (PRETEXT) stage, and LI-RADS major features of adult HCC. Imaging findings were compared between patients with and without predispositions. The study included 39 patients: 17 with predispositions (mean age, 10.5 ± 4.5 years; nine boys, eight girls) and 22 without predispositions (mean age, 11.3 ± 5.1 years; 12 boys, 10 girls). Scan indication was surveillance in 14/17 patients with predispositions versus 0/22 patients without predispositions ( < .001). Patients with versus those without predispositions had smaller tumor size (reader 1: 6.0 vs 11.9 cm [ = .003]; reader 2: 6.0 vs 12.9 cm [ < .001]) and less frequent tumor in vein (reader 1: 0% vs 41% [ = .002]; reader 2: 0% vs 36% [ = .006]). PRETEXT stage IV disease was observed in 18% (both readers) of patients with predispositions versus 50-55% of patients without predispositions. No LI-RADS major feature of adult HCC showed a significant difference in frequency between patients with and without predispositions for either reader (all > .05). Among children with HCC, those with predispositions exhibited smaller and lower-stage tumors and less frequent tumor in vein, likely because of surveillance imaging. The study supports the role of routine surveillance imaging in children with HCC predispositions to facilitate earlier detection. Standardization of surveillance guidelines remains needed.