Hepatocellular jaundice with abnormally high CA19-9: A case report.

[RATIONALE] Carbohydrate antigen 19-9 (CA19-9) is a mucin-type glycoprotein tumor marker that is present in trace amounts in normal human tissues, including the pancreas, bile ducts, stomach, colon, and salivary gland epithelium. In pancreatic cancer patients, the positive rate of CA19-9 exceeds 80%. Here, we report a case of hepatocellular jaundice accompanied by a marked elevation in CA19-9 levels.

[PATIENT CONCERNS] A 55-year-old female patient was admitted to our hospital with a 6-month history of abdominal distension and dark urine, which had worsened along with scleral jaundice over the past week.

[DIAGNOSES] The initial diagnosis upon admission was "jaundice under investigation." Laboratory investigations revealed a markedly elevated serum CA19-9 level of 284.8 units per milliliter, raising the possibility of an underlying neoplasm. However, no definite malignant lesions were detected on whole-body positron emission tomography-magnetic resonance imaging. The patient had a long-term history of chronic hepatitis B virus infection with a high viral replication state, suggesting chronic liver injury. Jaundice-related examinations showed elevated levels of total, direct, and indirect bilirubin, markedly abnormal transaminases, and positive urine bilirubin - findings consistent with the biochemical profile of hepatocellular jaundice. Abdominal computed tomography imaging revealed no biliary dilation, ruling out obstructive jaundice. The absence of anemia or abnormal hemolysis-related parameters argued against hemolytic jaundice. Although tumor markers (CA19-9 and alpha-fetoprotein) were transiently elevated, the absence of malignant masses on imaging and the subsequent normalization of CA19-9 levels following treatment led to the exclusion of malignancy-associated jaundice. The final diagnosis was confirmed as hepatocellular jaundice associated with viral hepatitis.

[INTERVENTIONS] The patient received active antiviral therapy, liver-protective treatment, and symptomatic supportive care.

[OUTCOMES] The patient's jaundice significantly subsided, and liver function parameters gradually improved. The patient was discharged after meeting the relevant criteria. A 6-month follow-up examination showed that CA19-9 levels had essentially returned to the normal range.

[LESSONS] This case demonstrates a significant and reversible elevation of CA19-9 in benign hepatocellular jaundice, the dynamics of which correlated with disease activity. It serves as a critical reminder that CA19-9 can be a misleading biomarker for malignancy in this clinical scenario.