Synchronous gastrointestinal stromal tumor and primary lung adenocarcinoma.

Although rare, gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. The asynchronous occurrence of other malignancies in patients with GIST during the clinical course is relatively common. However, the synchronous coexistence of GIST and lung cancer has only rarely been reported. We experienced a case of coincidental primary lung adenocarcinoma and intestinal GIST. The present case is not only of interest due to the rare coincidence of GIST and lung cancer, but also because there was an epidermal growth factor receptor gene mutation in the lung cancer and a c-kit mutation in the GIST.