Biloma formation after radiofrequency ablation of hepatocellular carcinoma: Incidence, imaging features, and clinical significance

OBJECTIVE. The objective of our study was to evaluate the frequency, morphologic patterns, temporal changes, and clinical significance of biloma after radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC). MATERIALS AND METHODS. Between April 1999 and May 2008, 2,630 patients with HCC underwent a total of 3,284 sessions of RFA at our institution. We retrospectively reviewed all CT scans obtained before and after RFA in all patients. The frequency, morphologic patterns, temporal changes, and clinical course of biloma were studied at the thermal ablation zone after RFA. RESULTS. A total of 109 bilomas (3.3%, 109/3,284) developed after RFA in 104 patients in our series. The bilomas developed from 0 to 526 days (mean, 64 days) after RFA, and the mean follow-up period was 469 days (range, 0-2,703 days). The most common morphologic type of biloma was a crescent shape (42.2%). The mean size of the bilomas at initial presentation was 3.8 cm (range, 1.7-11 cm), and the mean size of the bilomas on the last follow-up CT scan was 2.8 cm (range, 0-6.3 cm). Fifty-three (48.6%) of the 109 bilomas resolved during follow-up at a mean interval of 286 days. In one patient, the biloma was considered a major complication because percutaneous drainage was required to manage the biloma with infection (0.9%, 1/109). No patient died of a biloma. CONCLUSION. The development of a biloma after percutaneous RFA in patients with HCC was not rare. However, in most cases they were a minor complication of no clinical significance.