{'fraction_non_alphanumeric': 0.02326530612244898, 'fraction_numerical': 0.01020408163265306, 'mean_word_length': 5.1275, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Hepatobiliary and pancreatic: Delayed ileal perforation following radiofrequency ablation of hepatocellular carcinoma

An 80-year-old man was diagnosed with a recurrence of hepatocellular carcinoma on a contrast-enhanced computed tomography (CT) scan (arrow, Figure 1a). The tumor was approximately 8 mm from the liver edge and did not appear to be adjacent to the gastrointestinal tract. After infusion chemotherapy via the hepatic artery, ultrasound-guided radiofrequency ablation was performed under local anesthesia using a single internally cooled electrode with a 2-cm tip exposure. A CT scan obtained 1 day after radiofrequency ablation showed appropriate necrosis of the tumor without any apparent complications (arrow, Figure 1b). However, 14 days after radiofrequency ablation, the patient returned to the Emergency Department with abdominal pain. A repeat CT scan showed free air in the mesentery and thickening of the small bowel wall in the mid-abdomen. An early laparotomy was performed and revealed thermal damage to the ileum with a pinhole-sized perforation (arrow, Figure 2) but the damaged ileum was not adherent to the liver. The damaged segment was resected with an end-to-end anastomosis and the patient had an uneventful recovery. Radiofrequency ablation is an effective treatment for hepatocellular carcinoma with complication rates that range from 2% to 10%. Early complications include bleeding into the peritoneal or pleural cavities, perforation of the gastrointestinal tract and the development of a liver abscess. Late complications can include seeding of tumor along the electrode track and the development of strictures within the biliary system. In relation to intestinal perforation, a large multicenter study recorded 7 cases in 2320 patients, a frequency of 0.3%. Two of these patients died. The site of the perforation was the transverse colon in 5 patients and this appeared to be associated with adhesions in the upper abdomen. Perforations were also reported in the stomach (1 case) and jejunum (1 case). All patients with perforation had tumor within 1 cm of the liver capsule. In the above patient, the neoplasm was close to the capsule but adjacent bowel was not shown on a CT scan. However, the apparent absence of adjacent bowel does not exclude the possibility of intestinal perforation. Furthermore, the clinical features of perforation can be delayed for at least 2 weeks after radiofrequency ablation.