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Hepatobiliary and Pancreatic: Identification of recurrent hepatocellular carcinoma by intraoperative fluorescent imaging

An 81-year-old man was scheduled for surgery because of recurrent hepatocellular carcinoma (HCC) associated with hepatitis C. He had been previously treated with two liver resections. Magnetic resonance imaging using Gd-EOB-DTPA revealed a low-intense tumor in segment V in the portal (Figure 1 left) and delayed phases and a high-intense tumor in the arterial phase. Four days prior to operation, he had been given an intravenous injection of indocyanine green (0.5 mg/kg) to evaluate his hepatic reserve. The indocyanine green retention ratio at 15 minutes was 22.4%. In a previous study, we showed that indocyanine green was retained in liver cancer nodules for about 2 weeks and could act as a fluorescent source. After laparotomy and the dissection of adhesions, the lesion could not be identified by inspection or palpation and was not identified by intraoperative ultrasound or contrast-enhanced intraoperative ultrasound using Sonazoid (perfluorobutane, GE Healthcare, Oslo, Norway). Because of this, we attempted to identify the tumor at operation using a fluorescent imaging system (PDE, Hamamatsu Photonics, Hamamatsu, Japan). This showed clear fluorescence of the tumor on the liver surface (Figure 1 right). The resection line was marked with electrocautery after which he had a limited resection. Fluorescence of the tumor was also shown using fluorescent imaging on the resected specimen (Figure 2 left). The border of the tumor was vague and difficult to identify on gross examination (Figure 2 right) while pathological examination confirmed a wellto moderately-differentiated HCC of the small nodular type with an indistinct margin. This is the first report of the usefulness of an indocyanine green-fluorescent imaging technique for real-time identification of HCC that could not be identified by any other intraoperative technique. In our records from May 2008 to December 2009, we studied 113 HCCs in 79 patients that had been visualized by magnetic resonance imaging using Gd-EOB-DPA. When these were examined by intraoperative ultrasound or contrast-enhanced intraoperative ultrasound during surgery, five of these tumors (4.4%) could not be identified with either of the two intraoperative techniques. This may particularly apply to well-differentiated HCC that are often isoechoic during the delayed phase of contrastenhanced intraoperative ultrasound. Observations in the above case raise the possibility that intraoperative fluorescence after the use of indocyanine green may complement current intraoperative techniques that include inspection, palpation and the use of intraoperative ultrasound, with or without contrast agents.