[Suspected primary tumor in the diaphragm revealing large cell carcinoma in the lung with sarcomatous change]

A 59-year-old female was admitted to our institute with coughing. A primary tumor of the diaphragm was suspected by chest X-ray, CT and angiograms preoperatively. Intraoperative findings also suggested a large primary tumor in the diaphragm with invasion to the lung, pericardium and liver. Therefore, we performed partial resection of the diaphragm, lung, pericardium and liver all together through a right thoraco-abdominal approach and the diaphragm was reconstructed using polyglycolic acid mesh. Histologically, the large tumor located mainly in the diaphragm was sarcomatous, with transposition from the carcinomatous cells to the sarcomatous cells. A large cell tumor of the lung was also confirmed. Immunohistologically, the diaphragm tumor was positively stained by keratin and by epithelial membrane antigen. In addition, desmosomes were demonstrated under electron microscopy studies. The tumor of this case was sarcoma in the diaphragm developed from a minor large cell tumor in the lung. Though commonly thought difficult to prove sarcomatous change development from large cell tumor in the lung, we were able to determine this clearly with immunohistology and electron microscopy.