CASE REPORT: The patient was a 55-year-old man who had a past medical history of diffuse multiple liver abscesses. During follow-up examination, a hypovascular nodule measuring 2.1 cm in diameter was incidentally found in segment 8 of the liver. Surgical resection was performed based on a suspected diagnosis of hepatocellular carcinoma. A gastrofiberscopy examination detected characteristic findings of portal hypertensive gastropathy. During the laparotomy, multiple tiny cystic lesions were observed in a diffuse pattern across the liver surface. The liver parenchyma was slightly fibrotic and haemorrhagic. A histopathological examination revealed intrahepatic cholangiocarcinoma with vascular invasions in von Meyenburg's complex. Multiple biliary adenomas were also observed among the biliary microhamartomas adjacent to the main tumour, suggesting that the malignant transformation of the biliary adenomas might have been responsible for the development of the intrahepatic cholangiocarcinoma. The histopathologic examination also revealed sinusoidal dilation and abnormal spacing of the portal tracts and central veins as evidence of portal hypertension.
MATERIALS AND METHODS: Two hundred fifty-eight patients with primary liver tumors who underwent FDG-PET before LDLT were enrolled in this retrospective study. Unfavorable tumor histology was defined as primary liver tumor other than a well- or moderately differentiated HCC. Thirteen patients had unfavorable tumor histology, including 2 poorly differentiated HCC, 2 sarcomatoid HCC, 5 combined hepatocellular cholangiocarcinoma, 3 intrahepatic cholangiocarcinoma, and 1 hilar cholangiocarcinoma.
RESULTS: FDG-PET positivity was significantly associated with unfavorable tumor histology (P < 0.001). Both FDG-PET positivity and unfavorable tumor histology were significant independent predictors of tumor recurrence and overall survival. In a subgroup analysis of patients with FDG-PET-positive tumors, unfavorable tumor histology was a significant independent predictor of tumor recurrence and overall survival. High FDG uptake (tumor to non-tumor uptake ratio ≥ 2) was a significant predictor of unfavorable tumor histology. Patients with high FDG uptake and/or unfavorable tumors had significantly higher 3-year cumulative recurrence rate (70.8% versus 26.2%, P = 0.004) and worse 3-year overall survival (34.1% versus 70.8%, P = 0.012) compared to those with low FDG uptake favorable tumors.
CONCLUSIONS: The expression of FDG-PET is highly associated with histology of explanted HCC and predicts the recurrence. FDG-PET-positive tumors with high FDG uptake may be considered contraindication for LDLT due to high recurrence rate except when pathology proves favorable histology.