Hepatoduodenal lymph node metastasis mimicking Klatskin tumor in a patient with sigmoid colon mucinous cancer

We report a case of a 48-year-old female patient, who presented with abdominal pain, jaundice, and lack of appetite. Ultrasound showed intrahepatic biliary dilatation with retroperitoneal lymphadenopathy. Further magnetic resonance cholangiopancreatography detected Klatskin tumor. Computed tomography (CT) confirmed the Klatskin tumor with liver metastases and retroperitoneal lymphadenopathy. Biopsy from the hepatic lesion identified mucinous adenocarcinoma, likely originating from bile ducts. Endoscopic retrograde cholangiopancreatography was performed 3 times with stents placed in the left and right hepatic bile ducts. Later the patient had hematochezia and was referred to colonoscopy. Tubulovillous adenoma with dysplasia was diagnosed with signs of in situ cancer. Preoperative CT was done for further staging: new pulmonary metastases were discovered. Sigmoid colon was resected. Histopathology verified a poorly differentiated mucinous adenocarcinoma within the tubulovillous adenoma. Intraoperative biopsies of porta hepatis mass resembled metastatic lymph nodes in hepatoduodenal ligament, mimicking Klatskin tumor. Retrospective analysis of CT data demonstrated presence of sigmoid colon tumor.