Contrast-enhanced intraoperative ultrasound in the resection of colorectal liver metastases with intrabiliary growth.

A 68-year-old male who had undergone low anterior resection for primary rectal cancer 19 months ago presented with multiple CLM at Couinaud's segments IV, V, and VIII. There was no apparent macroscopic intrabiliary growth on preoperative computed tomography and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). However, the hepatobiliary phase of EOB-MRI revealed peritumoral low signal intensity in lesions in segments V and VIII, which indicates vascular invasion around hepatocellular carcinoma. Contrast-enhanced intraoperative ultrasound (CE-IOUS) clearly determined the extent of macroscopic glissonean growth from lesions in segments V and VIII, and more extensive resection was performed than was planned. Analysis of the resected specimens from segments V and VIII confirmed the presence of macroscopic intrabiliary growth with microscopic portal vein invasion. All three CLM were histopathologically diagnosed as well-to-moderately differentiated adenocarcinoma, and R0 resection was verified. Postoperative recovery was uneventful, and the patient was alive without evidence of recurrence 12 months after hepatic resection. CE-IOUS should be considered at the time of CLM resection, as it might enable more accurate detection of macroscopic intrabiliary growth of CLM, and enable resection with safer margins.