Affiliation: | (1) Department of Otolaryngology, Keiyukai Sapporo Hospital, Kita 1-1, Hondori 14-chome, Shiroishi-ku, Sapporo 003-0027, Japan;(2) Department of Surgery, Keiyukai Sapporo Hospital, Sapporo, Japan;(3) Keiyukai Institute of Clinical and Surgical Pathology, Sapporo, Japan;(4) Division of Medical Sciences, Health Sciences University of Hokkaido, Hokkaido, Ishikari-tobetsu, Japan |