FDG PET for the study of primary hepatic malignancies in children

This manuscript describes the use of FDG PET in a series of 7 children (11 scans) with primary hepatic malignancies (5 patients with hepatoblastoma, 2 patients with hepatic embryonal rhabdomyosarcoma), together with other imaging (CT and MRI), serum tumor markers, and tumor pathology.

Seven children with pathologically proven hepatic malignancies underwent 11 FDG PET scans for staging (1 patient) or restaging (6 patients). Tumor uptake of FDG was assessed qualitatively and compared with biochemical and radiological findings.

Abnormal uptake was demonstrated in 6 of 7 patients (10 of 11 scans). Three patients subsequently underwent partial hepatic resection, and one underwent brain biopsy, confirming in each that the abnormal uptake of FDG indicated viable tumor. In one patient, intense uptake was due to necrotizing granulomas. In one patient, images were suboptimal due to noncompliance with fasting.

Primary hepatic tumors of childhood usually demonstrate increased glycolytic activity, which allows them to be imaged using PET and the tracer 18F-FDG. The technique is probably most useful for assessing response to therapy, in following AFP (alfa fetoprotein) negative cases and for detecting metastatic disease although a large series of patients will need to be studied to confirm our initial findings. Non neoplastic inflammation may also accumulate FDG and could be confused with malignancy. As these tumors are rare, prospective multicenter studies are necessary to determine the true clinical utility of FDG PET imaging in the management of children with primary hepatic malignancies.