Two familial mesothelioma cases with high concentrations of soluble cytokeratin 19 fragment in pleural fluid.

We report two cases of diffuse malignant pleural mesothelioma occurring almost simultaneously in one family. Patient 1 was a 42-year-old Japanese man who had worked as an electrical engineer for 25 years. Patient 2, his mother, was 69 years old. She lived for 10 years with patient 1 after he started his work, and also worked at a shipyard herself for 6 years. The concentrations of cytokeratin subunit 19 fragment (CYFRA 21-1) in pleural fluid of the two patients were 1,500 ng/ml, and 1,200 ng/ml, respectively. Measurement of CYFRA 21-1 concentration in the pleural fluid may be a useful tool for a diagnosis of malignant mesothelioma.