Synchronous four primary lung adenocarcinoma associated with multiple atypical adenomatous hyperplasia.

A 69-year-old woman with synchronous bilateral 4 primary lung adenocarcinoma accompanied by multiple atypical adenomatous hyperplasia (AAH) is described. The patient was found to have bilateral multiple tumors during a preoperative chest CT evaluation which was performed for the previously-diagnosed adenocarcinoma of the right middle lobe. Since intraoperative diagnosis of the left nodular lesion was adenocarcinoma and judged to be a pulmonary metastasis, a lobectomy of the right middle lobe only was performed. Postoperative pathological diagnosis including immunohistochemical findings demonstrated that the bilateral lesions were synchronous multiple primary adenocarcinoma, independent of each other and associated with multiple AAH. This case suggests the possibility of the AAH-adenocarcinoma sequence in the development of lung cancer. In addition, the strategy of treatment for synchronous multiple adenocarcinoma should be considered.