Elevated Creatine Kinase as a marker for aggressive GI malignancy

Klatskin tumor is a rare and aggressive biliary malignancy with a poor prognosis. We present a 72-year-old male with a history of COPD and severe non-ischemic cardiomyopathy who presented with jaundice, pruritus, and fatigue. Laboratory findings revealed marked hyperbilirubinemia and elevated liver enzymes, along with significantly increased creatine kinase (CK). Imaging studies and ERCP confirmed the diagnosis of perihilar cholangiocarcinoma, Bismuth class III, with adenocarcinoma pathology. Despite palliative stent placement, the patient's bilirubin levels remained elevated, and CK peaked at 45,000 units/L. Due to his advanced disease and comorbidities, he was not a candidate for surgical or systemic therapy and was transitioned to home hospice. This case highlights the diagnostic and therapeutic challenges in managing Klatskin tumors and the importance of recognizing significant elevation in CK, which in the absence of signs of muscle breakdown/pain may hypothetically correlate with aggressive forms of gastrointestinal malignancies.