Atypical adenomatous hyperplasia is a premalignant lesion reflecting a focal proliferation of atypical cells. These lesions are usually observed as incidental findings in lungs that have been resected due to other conditions, such as lung cancer. We report the youngest case of atypical adenomatous hyperplasia on record in a 12-year-old girl. In this patient, the lesion was found in association with pneumothorax.
Keywords: Lung pathology; Neoplasm; Pneumothorax; Thoracoscopy.