Complete spontaneous necrosis of hepatocellular carcinoma accompanied by portal vein tumor thrombosis: A case report

INTRODUCTION We report a rare case of complete spontaneous necrosis of a hepatocellular carcinoma (HCC) accompanied by portal vein tumor thrombosis (PVTT), as confirmed by resection. CASE PRESENTATION A 64-year-old man was referred to our hospital for suspected HCC. Contrast-enhanced computed tomography (CECT) findings before admission revealed a 53-mm tumor in the posterior segment of the liver and were suspicious for PVTT in the right posterior PV. Both alpha-fetoprotein (AFP) and proteins induced by vitamin K absence or antagonist-II (PIVKA-II) were elevated at 17,562 ng/mL and 153 mAU/mL, respectively. We diagnosed the findings as HCC with PVTT. Seven days after the first CECT scan, we performed CECT volumetry, which revealed that the tumor had regressed to 30 mm, along with regression of the PVTT. We performed portal vein ligation (PVL), and 10 days later, CECT revealed that the tumor had shrunk to 20 mm. AFP and PIVKA-II levels were 643 ng/mL and 14 mAU/mL, respectively. We suspected spontaneous regression of the patient's HCC, but performed a hepatectomy. Histopathology revealed a 22-mm tumor with a thin fibrous capsule and a tumor thrombus in the PV. Trabecular and pseudoglandular structures consisting of denucleated HCC epithelial cells made up both the tumor and thrombus, and the finding confirmed the spontaneous necrosis of HCC. CONCLUSIONS We present an extremely rare case of complete spontaneous necrosis of HCC with PVTT. When spontaneous necrosis is suspected, surgery should be considered because of the potential risk of residual viable cancer cells.