Primary non-hepatoblastoma liver tumors in children-Defining the profile of a very rare subset of childhood tumors.

[BACKGROUND] Primary pediatric non-hepatoblastoma (n-HB) liver tumors are rare with limited literature on their clinical-epidemiological profile and outcomes. We audit the above in this study.

[METHODS] Children diagnosed with n-HB primary liver tumors from January 2012 to December 2023 were analyzed retrospectively. Patients underwent contrast-enhanced computed tomography (CECT) of the abdomen and computed tomography (CT) of the thorax or fluorodeoxyglucosepositron emission tomography/computed tomography (FDG-PET/CT) for staging of malignant tumors. Treatment was administered based on the definitive diagnosis.

[RESULTS] Sixty-nine patients formed the study cohort. The most common tumors in various age groups were infantile hepatic hemangioma (IHH)-66.7%, malignant rhabdoid tumor (MRT)-25%; six months to three years: MRT-25.0%, mesenchymal hamartoma and hemangioendothelioma-18.7% each; three to 10 years: hepatocellular carcinoma (HCC)-31.6%, undifferentiated embryonal sarcoma of the liver (UESL)-26.3%; and > = 10 years: HCC-45.4%, UESL-22.7%. Median alpha-fetoprotein (AFP) level in HCC was 131,249 ng/mL. Treatment was delivered to 65.8% patients. Chemotherapy for treated malignant tumors was administered in 81.5%, surgery in 85.2% and radiotherapy in 18.5%, alone or combined. In the different malignant cancer sub-types, the proportion of relapse/deaths in treated patients was HCC-22.2%, UESL-33.3%, rhabdoid-25%, hemangioendotheliomas-25% and sarcomas-25%.

[CONCLUSIONS] There was a high proportion of malignant rhabdoid tumors and higher serum AFP levels in HCC in our cohort. The overall outcomes of treated malignant tumors were relatively favorable, though limited by the sample size in this rare cohort.