An Unusual Presentation of Cholangiocarcinoma: The Sister Mary Joseph Nodule—A Case Report

<b>Background and Clinical Significance</b>: Sister Mary Joseph nodules (SMJN) are rare extra-intestinal manifestations of metastatic intra-abdominal and pelvic malignancies, often indicating advanced disease and poor prognosis. Their association with cholangiocarcinoma (CCA) is particularly uncommon, with only a limited number of reported cases. <b>Case Presentation</b>: We present a case report of a 65-year-old previously healthy male who presented for an elective umbilical hernia repair. Additional findings of elevated direct bilirubin and a history of fatigue in the patient prompted further evaluation with biopsy and imaging, which revealed advanced-stage intrahepatic CCA. Following the diagnosis, the patient underwent biliary stenting and chemotherapy. <b>Conclusions</b>: The variable presentation of SMJN, along with its frequent misdiagnosis, often delays recogni-tion and management of the underlying malignancy. This case of SMJN in the setting of CCA highlights the complex interplay between intra-abdominal and pelvic malignancies and their impact on different organ systems. With the rising incidence and mortality rates associated with CCA, early recognition is essential to improving patient outcomes. This underscores the need for increased clinical awareness and further research, thus support-ing the development of this case report.