[Case of exostosis of the hard palate disturbing the insertion of Pro-Seal laryngeal mask].

We report a case of exostosis of the hard palate which had not bean ruled out in pre-operative examination and disturbed insertion of Pro-Seal laryngeal mask. The hard palate has canopy construction, and it is difficult to find this exostosis by routine physical examination. When we use Pro-Seal laryngeal mask, a careful inspection of the hard palate is indispensable.