食道扁平乳頭腫の臨床病理学的・免疫組織化学的検索

Squamous Cell Papilloma of the Esophagus: A Clinicopathological and Immunohistochemical Study of 156 Lesions

　食道扁平乳頭腫151症例，156病変を対象として臨床病理学的および免疫組織化学的立場から検討した．平均年齢は60.5歳，男女比は1：1.4でやや女性に多く，中部食道に好発した（51.9％）．形態学的に外方へ向かって増殖するexophytic type（75.0％），内方への増殖を示すendophytic type（23.1％），スパイク状の尖った上皮を呈するspiked type（1.9％）の3型に分けられ，各群のkoilocytosis，parakeratosis，炎症細胞浸潤の程度およびKi-67 labeling index（L. I.）には明確な差を認めなかった．Ki-67 L.I.は，上部食道（25.6±9.6％）に比し下部食道（34.6±14.6％）に発生したもので，また炎症細胞浸潤の程度が高度なもので有意に高かった．抗human papillomavirus（HPV）抗体陽性細胞は22病変（14.1％）に認められた．以上より，食道扁平乳頭腫には炎症細胞浸潤による上皮の反応性増殖とHPV感染による増殖が存在することが示唆された．全例において上皮に明らかな異型はなく悪性所見も認めなかったが，HPVには癌化に関与するタイプも存在し，少なくとも経過観察は必要と考えられた．

　We analyzed the clinical data and histological features of 156 squamous cell papillomas (ESPs) of the esophagus from 151 patients and carried out immunohistochemical staining of Ki-67 and anti-human papillomavirus (HPV) to define the proliferative activity and the correlation of HPV with ESP. Clinically, females were affected more often than males (M:F ratio＝1:1.4); average age was 60.5 (range, 17-88 years). More than half of ESPs were located in the middle esophagus. We classified ESPs histologically into three types (exophytic, 75.0％;endophytic, 23.1％;spiked, 1.9％). The average Ki-67 labeling index (L.I.) was 31.0％. Ki-67 L.I. of the lower esophagus was significantly higher than that of the upper esophagus, and a higher Ki-67 L.I. was observed in the ESPs with more severe inflammatory infiltration. The 22 lesions (14.1％) were immunohistochemically positive for anti-HPV antibody. These findings are consistent with both of the two etiologic factors;chronic mucosal irritation and infection of HPV.