Clinical usefulness of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography for patients with primary liver cancer with special reference to rare histological types, hepatocellular carcinoma with sarcomatous change and combined hepatocellular and cholangiocarcinoma

Aim: The role of ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the diagnosis and staging of primary liver cancer has been demonstrated in several reports. However, no preoperative evaluations of sarcomatous hepatocellular carcinoma (HCC) and combined hepatocellular and cholangiocarcinoma (cHCC-CC) with FDG-PET have been reported so far. Methods: Fifty-three HCC patients and three cHCC-CC patients who received liver resection or living-donor liver transplantation were enrolled in this study. All 56 patients had undergone preoperative FDG-PET, and a total of 67 HCC and three cHCC-CC were analyzed histologically. The relationship between clinicopathological features and the maximum standardized uptake value (SUVmax) of tumors were evaluated. Results: The detection rate of HCC by FDG-PET was 43.3 %, and the sensitivity of FDG-PET for the detection of HCC was significantly associated with tumor differentiation, tumor size and microvascular invasion. All three cHCC-CC were detected by FDG-PET. The SUVmax values of the three sarcomatous HCC (SUVmax 14.1, 18.6 and 25.0) and the three cHCC-CC (SUVmax 9.9, 12.0 and 13.0) were higher than that of the poorly differentiated HCC (mean SUVmax 5.7±2.3). Conclusion: SUVmax may be a useful diagnostic tool for the preoperative evaluation of the aggressiveness of primary liver cancers such as sarcomatous HCC and cHCC-CC.