Application of Indocyanine Green Fluorescence Imaging to Pediatric Hepatoblastoma Surgery

Abstract

We will elaborate on navigation surgery using indocyanine green (ICG) fluorescence imaging in pediatric hepatoblastoma. Chemotherapy is effective against hepatoblastoma, and while complete surgical resection of the primary lesion can often result in recovery, prognosis in patients with distant metastases is poor. In recent years, the importance of proactively resecting lung metastases has been highlighted. Previously, metastases discovered during visual inspection and palpation were resected; however, this approach lacked objectivity and was subject to the skill of the surgeon. Using ICG fluorescence method has facilitated the intraoperative discovery of micrometastases. In ten patients in which lung metastases were detected, we used ICG fluorescence imaging and resected a total of 250 fluorescence-positive masses. The smallest metastasis had a diameter of 62 μm. Twenty-nine masses were false-positives; these were concentrated in two patients. When observing biopsy samples of the false-positive masses under a fluorescence microscope, luminescent thrombi and granulomas were apparent. The reason for the fluorescence is unknown, although it is possible that the masses contained micrometastases with diameters that were too small to be histopathologically identified. There were no false-negatives. ICG fluorescence imaging was also demonstrated to be an effective method for identifying metastases in the lymph nodes and peritonea. Additionally, as in surgery for hepatocellular carcinoma in adults, ICG fluorescence imaging was useful for hepatoblastoma, in terms of identifying tumors during primary liver tumor resection, and for intraoperative cholangiography.