特異な組織型を呈し内視鏡治療後転移を来したBarrett腺癌─ESD施行後に肝転移を来した扁平上皮への分化を伴う表在型Barrett食道腺癌の1例

Superficial pT1b-SM2 Barrett's Esophageal Carcinoma of Special Histological Type with Liver Metastasis, Report of a Case

要旨●患者は70歳代，男性．通常観察にてSCJ直下2時方向に径15mm大のくびれを有する発赤調隆起性病変を認め，頂部はやや陥凹していた．NBI併用拡大観察では，表面構造は小型の乳頭・顆粒状構造と口径不同を伴う異常血管を認め，深達度T1a（M）と判断した．2か月後の通常観察では明らかに腫瘍は増大し緊満感を認め，深達度T1b-SM2と診断したが，CT検査上リンパ節転移を認めなかったため，高齢・合併症を考慮し局所制御を目的にESDを施行した．病理学的診断はadenocarcinoma with squamoid（or basaloid）differentiation in part，pT1b（SM2, depth：about 3,000μm），ly0，v1（marked），pHM0，pVM0，23×15mm．粘膜下層浸潤部および静脈浸潤組織像は扁平上皮への分化を示唆する充実性低分化型癌あるいはbasaloid carcinoma様の癌を呈していた．ESD施行4か月後に肝S4に転移を認めたため拡大肝左葉切除を行い，病理組織学的には原発巣のSM浸潤部と同様の組織像を呈していた．ESD施行7か月後には多発肺転移を認め，ESD施行1年3か月後に肺癌性リンパ管症で原病死した．

　A male in his seventies undergoing conventional esophagoscopy due to hematemesis was found to have a reddish, protruded, narrow-based lesion on the right wall of the SCJ（squamo-columnar junction）. The background mucosa of the tumor was diagnosed as short-segment Barrett mucosa of the because of the presence of squamous islands on the distal side of SCJ. NBI（narrow band imaging）with magnification for this lesion revealed a high density of a small papillary/granular pattern with an irregular microvascular pattern．The initial tumor depth was identified as cT1a（M）. However, the size of this tumor clearly increased with a firm consistently after 2 months, suggesting massive invasion of the submucosal layer. We performed ESD（endoscopic submucosal dissection）because of the absence of contraindications, including advanced age, previous severe complications, and lymph node or distant metastases on CT（computed tomography）examination. Histopathologically, the tumor was diagnosed as a 23 2315mm esophageal adenocarcinoma with partial squamoid（or basaloid）differentiation, pT1b（SM2, depth：approximately 3,000μ0）, ly0, v1（marked）, pHM0, and pVM0. The region of submucosal invasion demonstrated a special histological type that differed from the common histological type of Barrettccasion tionith n. evere complications, and y due to he at this time. Liver metastases were detected by abdominal CT at 4 months after ESD, and extended left hepatic lobectomy was performed. The histology of resected liver specimens resembled the region of primary submucosal invasion.