A 75-year-old man presented to the hospital with jaundice that had been present for 1 month. He had a medical history of hypertension and non-tuberculosis mycobacterial infection but no surgical history. Laboratory findings showed elevated levels of serum bilirubin and liver enzymes: total bilirubin, 10.6 mg/dL; aspartate aminotransferase, 68 IU/L; alanine aminotransferase, 119 IU/L; and gamma-glutamyl transpeptidase, 393 IU/L. Serum carbohydrate antigen 19-9 was also elevated (54.8 U/mL), though carcinoembryonic antigen was within the normal range. Enhanced computed tomography (CT) revealed a well-enhanced tumor in the distal bile duct and dilation of the hepatic bile duct (Figure 1(a)). In addition, the gallbladder mucosa was thickened, with a homogeneous contrast effect (Figure 1(b)). Magnetic resonance imaging (MRI) showed a low T2 signal tumor in the common bile duct (Figure 2(a)), and magnetic resonance cholangiopancreatography (MRCP) showed dilation of the hepatic-sided bile duct from the tumor (Figure 2(b)). The thickened gallbladder walls had a homogeneous low T2 signal; however, liver invasion by the tumor was not significant. Endoscopic retrograde cholangiopancreatography (ERCP) revealed a filling defect in the distal bile duct, and the cystic duct was invisible (Figure 3(a)). Moreover, intraductal ultrasonography (IDUS) showed a papillary tumor in the common bile duct and indicated invasion of the bile duct subserosa (Figures 3(b) and 3(c)). Subsequent bile duct brushing cytology on ERCP and IDUS revealed adenocarcinoma, and the patient was diagnosed with distal bile duct cancer associated with adenomyomatosis of the gallbladder.
The patient was referred to our hospital for surgical treatment, and we planned to perform PPPD for distal bile duct cancer with curative intent. Intraoperative findings revealed a thickened and indurated gallbladder wall, suggesting the coexistence of gallbladder cancer; thus, we performed PPPD and extended cholecystectomy. Intraoperative frozen-section analysis of the cut end of the hepatic bile duct was negative for the tumor. A macroscopic examination of the resected specimen revealed a papillary tumor that had extensively invaded the liver, cystic duct, bile duct, and pancreas (Figures 4(a) and 4(b)). Permanent histopathological findings indicated that the tumor was papillotubulary and had broad-based growth of columnar cells with mucus production in the gallbladder (Figures 5(a) and 5(b)). In addition, metastasis to the lymph nodes of the hepatoduodenal ligament was observed. Immunohistochemical analysis revealed that the tumor cells were positive for mucin (MUC)1, MUC5AC, and MUC6, but negative for MUC2 and p53 (Figures 5(c), 5(d), and 5(e)). Finally, the diagnosis of gastric-type ICPN was established according to the 2010 WHO classification. The postoperative course was uneventful, and the patient started adjuvant chemotherapy (tegafur/gimeracil/oteracil) 1 month after surgery. At the follow-up after 1 year, the patient had no recurrence.