Inverted Urothelial Papillomaとその類似腫瘍

Abstract

Inverted urothelial papillomaの2例と, 最近5年間の膀胱生検および手術材料173検体から選択したinverted growthとmicrocyst formationを有する2例の高分化移行上皮癌(Inverted papilloma類似腫瘍)を病理組織学的に比較検討し, さらにInverted papillomaの本邦報告例40例の集計と文献的考察もあわせておこなった.Inverted papillomaの発生は, 尿路上皮癌同様のcarcinogenの関与によって腫瘍化した上皮の下方増殖によるものと考えられた.Inverted papillomaに見られるmicrocystは, 腫瘍性上皮に残された移行上皮の腺上皮的性格, あるいは腫瘍性の上皮化生に由来するものと思われた.いわゆる慢性増殖性膀胱炎とInverted papillomaの併存を認めたが, 後者が前者を経て発生したものとは考えがたかった

Two cases of inverted papilloma, developed on the bladder neck in 36- and 23-year old males, are presented. From the Japanese literature, 40 cases of inverted papillomas have been collected and are reviewed. In addition, a review of the consecutive series of 173 pathological specimens, obtained by bladder biopsy and at the time of bladder surgery over the past 5 years disclosed a resembling lesion in two cases of bladder tumors. An inverted growth of transitional-cell carcinoma was observed in one case. Transitional-cell carcinoma with abundant microcysts was covered by the non-neoplastic transitional-cell epithelium in the other case. In conclusion, the inverted urothelial papilloma is more likely an inverted growth of the neoplastic epithelium with epithelial metaplasia and microcyst formation, much as is observed in so-called chronic proliferative cystitis, than a neoplastic transformation from chronic proliferative cystitis.