Successful liver resection for the unusual case of peripheral intra bile duct growth of liver metastasis from colorectal carcinoma
A 67-year-old male patient underwent emergency left hemi-colectomy due to ileus caused by descending colon cancer. The pathological examination was consistent with adenocarcinoma (T3N1M0). Sixteen months following resection, there was a significant increase in routine follow-up carcinoembryonic antigen 19-9 (CA19-9): 607.7 U/ml.\nComputed tomography (CT) demonstrated two solitary lesions in segment (S) eight. Furthermore, S3 hepatic duct dilatation was clearly detected on CT scanning (Fig. ).\nMagnetic resonance imaging (MRI) of the lateral segment lesion showed an irregular line shape lesion: hyper-intensity in T2-weighted; hypo-isointense in T1-weighted image (Fig. ). These CT and MRI findings supported the identification of a fulfilment of tumour in B3. Endoscopic retrograde cholangiopancretography (ERCP) demonstrated a stricture involving the B2 and B3 hepatic ducts but not involving the left hepatic duct. Considering the patient's medical history along with the clinical features, the final diagnosis was secondary liver metastases due to primary descending colon adenocarcinoma, with the possibility of peripheral cholangiocarcinoma.\nIn order to obtain efficient bile duct tumour clearance as well as to maintain liver function (15-min retention rate of Indocyanine green: 19%), the patient underwent anatomic S8 resection and lateral segmentectomy (Fig. ). The metastasis in the lateral segment demonstrated intra bile duct tumour growth.\nAlthough there was B3 intra bile duct growth, there was no pathological evidence of malignancy in the left main bile duct. For the S8 metastases, systemic S8 resection with indigo carmine S5 counter strain had also been performed. Subsequently, normal anatomic lateral segmentectomy was performed without extra hepatic bile duct resection or cholecystectomy. His clinical course was stable without complications, and he was discharged after 7-days of hospitalisation. The patient is currently suffering from amyotrophic lateral sclerosis, without any sign of local metastatic tumour recurrence 14 months post-operatively.\nPathological examination for the descending colon carcinoma revealed an adenocarcinoma which was well differentiated, with one out of ten lymph node metastasis identified (Dukes' C). Macroscopically, the surgical specimen of the liver demonstrated a papillary tumour with clear margin intra and extra hepatic duct growth. On microscopic examination, the histological differentiation of the three metastatic tumours was identical to that of the descending colon cancer. The lateral segment tumour was located in the intrahepatic duct which demonstrated cytokeratin (CK) 7(+), CK20(−) and caudal-type homeobox (CDX2) (−). These findings are consistent with liver metastases due to colorectal adenocarcinoma []. The S8 metastases did not reveal intra biliary tumour growth. Following this histological finding, the tumour invaded into hepatic duct, followed by the hepatic duct being filled with metastatic tumour at S3.