[Papillary adenoma of type-II pneumocytes as a rare differential diagnosis of a solitary pulmonary nodule].

The case of a 66-year-old, asymptomatic patient with a papillary adenoma of type-II pneumocytes is reported. Following the coincidental radiologic finding of a solitary pulmonary nodule, the diagnosis could be established in a bronchoscopically obtained endobronchial biopsy. A resection of the involved segments S8-10 on the left side was performed. Papillary adenoma of type-II pneumocytes is a rare tumor, whose origin is suspected in progenitor cells of the bronchioloalveolar epithelium with the potential to differentiate towards type-II pneumocytes and clara cells. The tumor is regarded as benign, however, a malignant potential is not excluded by some authors.