Intrapancreatic bile duct metastasis from colon cancer after resection of liver metastasis with intrabiliary growth: a case report

A 73-year-old man was examined at our hospital in February 2014 for a chief complaint of epigastric abdominal pain. Computed tomography (CT) was performed and clearly depicted a mass with clustered calcifications in the intrapancreatic bile duct, which was dilated (Fig. 1). The patient’s medical history, which we describe below, led to a diagnosis of residual intrapancreatic bile duct cancer.

The patient had undergone sigmoidectomy in October 1993 for a sigmoid colon cancer, which had the macroscopic appearance of a Borrmann type I tumor with a partial papillary structure and was 2.0 cm in diameter. Histologic examination of the surgical specimen revealed a well- to moderately differentiated adenocarcinoma forming the papillary structure (Fig. 2). The neoplasm was judged, according to the UICC TNM classification system, to be a stage IIA tumor that had infiltrated beyond the muscularis propria but without lymph node metastasis (pT3, N0, M0). No adjuvant therapy was performed, and the patient was followed up for 5 years with no evidence of recurrence. Nine years after the sigmoidectomy, obstructive jaundice developed, and contrast-enhanced CT revealed dilatation of the intrahepatic bile duct extending from the posterior segments of the right lobe to the common hepatic duct and a low-density mass within the duct (Fig. 3). Intrahepatic cholangiocarcinoma was diagnosed. Percutaneous transhepatic biliary drainage was performed, and this was followed by extended right hepatic lobectomy and caudate lobectomy with extrahepatic bile duct resection in December 2002. Roux-en-Y hepaticojejunostomy was performed, with the jejunal limb placed in the retrocolic retrogastric position. Macroscopically, the mass appeared as a papillary lesion in the posterior segmental bile duct that drains into the common hepatic duct. Histologic examination revealed a well-differentiated adenocarcinoma forming an intrabiliary papillary tumor and invading the liver at the posterior segmental bile duct that drains into the right hepatic duct (Fig. 4). Both the proximal and distal margins of the resected specimen were free of cancer cells. The postoperative diagnosis at that time was stage I intrahepatic cholangiocarcinoma (T1, N0, M0).

The patient was followed up regularly after the hepatectomy, and at 2 years and 10 months, contrast-enhanced CT revealed intrapancreatic bile duct dilatation, but no cancerous lesion was detected, so the routine follow-up examinations were continued until February 2014, when the residual intrapancreatic bile duct cancer was discovered. The discovery was followed by performance of subtotal stomach-preserving pancreatoduodenectomy in April 2014. The previous bilio-enteric anastomosis was preserved (Fig. 5). The operation time was 229 min, and the blood loss volume was 630 mL. There was no intraoperative complication. However, a grade B postoperative pancreatic fistula (International Study Group on Pancreatic Fistula (ISGPF) classification) developed [4], and thus, the patient’s postoperative hospital stay was 30 days. Macroscopically, a papillary lesion measuring 70 × 40 mm was noted in the remnant intrapancreatic bile duct. Histologic examination revealed a well-differentiated adenocarcinoma with invasion into the pancreas but no lymph node metastasis. There was no evidence of lymphatic, vascular, or perineural invasion (Fig. 6). At this stage, the tumor was diagnosed as a remnant intrapancreatic bile duct cancer, but the histologic type, based on hematoxylin-eosin staining, was identical to that of the sigmoid colon cancer found in 1993 and the “intrahepatic cholangiocarcinoma” found in 2002. Furthermore, the macroscopic types of the three specimens were similar. Immunohistochemically, the cytokeratin and mucin core protein expression patterns were similar. All three specimens were negative for cytokeratin 7 (CK7) and positive for cytokeratin 20 (CK20) (Fig. 7). This expression pattern was indicative of metastatic adenocarcinoma, which most often arises from the colon or rectum [5]. In addition, neighboring biliary epithelium was CK7-positive and CK20-negative. All three specimens were weakly positive for Mucin2 (MUC2) but negative for Mucin1 (MUC1), Mucin5AC (MUC5AC), and Mucin6 (MUC6). In reviewing the case history, we recalled that a very low-density mass had been depicted in the intrapancreatic bile duct in October 2005 and it had gradually enlarged over several years (Fig. 8). We concluded that the intrabiliary tumor found in 2002 was a liver metastasis arising from the sigmoid colon cancer and showing intrabiliary growth and that the intrapancreatic bile duct tumor originated from the spontaneous shedding of the biliary tumor thrombus or from the implantation of tumor cells as a complication of percutaneous transhepatic biliary drainage. Twelve months have passed since the last surgical intervention, and there has been no sign of local recurrence or distant metastasis.

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.