A tumor on the larynx (voice box) that is usually benign and resembles a wart. Laryngeal papillomas are believed to be caused by a virus. They usually develop in groups and may cause difficulty breathing, in addition to hoarseness. Rarely, papillomas will grow large very quickly. In these instances, they may obstruct breathing and should be treated as soon as possible to prevent total blockage of the air supply. In recent years, laser treatment has yielded more satisfactory results than traditional surgical procedures for removing laryngeal papillomas.