False-Positive Elevation of CK-MB Levels with Chest Pain in Lung Adenocarcinoma

The creatinine kinase (CK)-MB assay can be used for the early diagnosis of acute coronary syndrome. We describe the case of an 82-year-old male with lung adenocarcinoma who presented with chest pain. While laboratory findings showed elevated CK-MB levels, there was no cardiac injury. A chest computed tomography scan revealed pleural carcinomatosis. Later, electrophoretic analysis of CK showed a normal CK-MB range but increased CK-BB levels and the presence of macro CK type 2. We determined that the patient's chest pain originated from the visceral pleural invasion of lung cancer. Because of the methods used to measure the CK-MB isozyme, the CK-MB level appeared elevated.