[Pulmonary metastasis after resection of non-invasive thymoma: a case report--analysis of nuclear DNA pattern and pathological findings].

After resection of a non-invasive thymoma, two metastatic lung tumors were found in the left upper lobe and the left lower lobe. There were differences in tumor doubling time (TDT) and invasion between the metastatic tumor in the lower lobe and the one in the upper lobe. The TDTs of the tumors were 834.1 days and 328.3 days, and the tumor of the left lower lobe invaded the left lateral basal segmental bronchus (B9). The differences in the two tumors were determined by pathological findings and nuclear DNA pattern. Pathologically, the resected thymoma and both of the metastatic tumors were mixed type, which consisted of epithelial cells and lymphocytes. But by epithelium form, the resected thymoma and the tumor in the lower lobe were classified as cortex type, and only the slow growing tumor in the upper lobe contained a spindle-cell component. The DNA pattern of the resected thymoma was aneuploid and the two metastatic tumors were diploid. As this case is very interesting clinically and pathologically, we reported it.