Normal Tumor Markers and Increased Adenosine Deaminase in Pericardial Effusion Misdiagnosed as Tuberculous Pericarditis Ultimately Proven as Lung Adenocarcinoma with Pericardial Metastasis: a Case Report and Literature Review

Background: Elevated adenosine deaminase (ADA) and normal tumor markers in pericardial or pleural effusion are usually considered to be a specific manifestation of benign pericardial or pleural effusion. Here we report a case of lung adenocarcinoma with pericardial metastasis with elevated ADA and normal tumor markers in pericardial effusion. Methods: Pericardiocentesis and lung puncture combined laboratory indexes and pathology were performed for diagnosis. Results: Analysis of pericardial fluid revealed a white blood cell (WBC) count of 2,000 x 10(6)/L (70% for lymphocytes) with an ADA level of 72.8 U/mL. Pathology of pericardial effusion found no malignant cells. Histopathology of percutaneous lung puncture showed adenocarcinoma. Conclusions: ADA and tumor markers were not a specific index in differential diagnosis between tuberculosis and metastasis in pericardial effusion.