Abstract

Atypical adenomatous hyperplasia (AAH) is regarded as a precancerous lesion in the multistep process for carcinogenesis of pulmonary adenocarcinoma. AAH is found in up to 25% of the lung tissue adjacent to cancer, particularly adenocarcinoma and also in 2-4% of autopsy cases. Until now, its main clinical significance is that some tumor recurrences are the lesions that have progressed from undetected AAH or they are newly developed cancers arising from AAH during the follow-up after the resection of adenocarcinoma. We present here the case of a 58-year-old woman having a large main adenocarcinoma with multiple small AAHs that mimicked lung-to-lung metastasis. AAH should be considered in the differential diagnosis of multiple small nodules during the preoperative evaluation and also during the follow-up of lung cancer patients.

• Keywords: Atypical adenomatous hyperplasia;Metastasis;Lung;