Columnar papilloma of the bronchus. Case report and literature review.

Solitary papillomas are rare endobronchial neoplasms that are most commonly lined by a squamous epithelium (i.e., squamous papillomas). Papillomas exhibiting nonsquamous epithelium are even more unusual; only seven solitary papillomas lined by columnar epithelium (i.e., columnar papillomas) have been previously described. The current report presents the eighth patient with a columnar papilloma and demonstrates some features common to solitary papillomas (i.e., central location in the airways, associated atelectasis), but distinctive from squamous papillomas (i.e., absence of malignant potential).