川端 聡¹, 尾羽根 範員¹, 西村 重彦², 吉川 淳一¹, 津村 京子¹, 仙崎 菜々恵¹, 多久和 幸恵¹, 堤 直哉¹, 吉永 仁香¹, 壷井 萌乃香¹

Satoshi KAWABATA¹, Norikazu OBANE¹, Shigehiko NISHIMURA², Junichi YOSHIKAWA¹, Kyoko TSUMURA¹, Nanae SENZAKI¹, Sachie TAKUWA¹, Naoya TSUTSUMI¹, Kimika YOSHINAGA¹, Honoka TSUBOI¹

¹住友病院臨床検査科, ²住友病院外科

¹Department of Clinical Laboratory, Sumitomo Hospital, ²Department of Surgery, Sumitomo Hospital

キーワード : pancreatic carcinoma, carcinoma in situ, ultrasound, focal pancreatic parenchymal atrophy （FPPA）, ultrasound examination

近年CT，MRIにて限局性膵萎縮を指摘して発見される膵上皮内癌の報告例が多くみられる．しかしこれまで体外式超音波（US）による報告はみられず，その超音波像は明らかとなっていない．今回我々はスクリーニングUSにて偶然，限局性膵萎縮を認めて発見された膵上皮内癌を経験したので報告する．症例は60代男性．肺化膿症にて入院中に施行された腹部スクリーニングUSにて限局性膵萎縮と主膵管狭窄および尾側膵管拡張を認めた．主膵管壁の断裂がなく腫瘤像もみられなかったことから膵上皮内癌を疑い精査となった．CT，MRI，EUS，ERCPいずれの検査でも膵癌が疑われ，連続膵液細胞診（SPACE）にて異型細胞が検出されたため膵体尾部切除術が施行された．最終診断はStage 0の膵上皮内癌であった．限局性膵萎縮は上皮内癌の段階で主膵管拡張よりも早期に出現すると報告されている．USにて膵長軸像での輪郭の不自然な陥凹像は限局性膵萎縮として認識でき，検診USでこの所見を検出することができれば多くのStage 0膵癌の発見が期待できると考える．

There are many reported cases of pancreatic carcinoma in situ discovered based on focal pancreatic parenchymal atrophy detected on CT or MRI. However, there have been no reports of US findings to date, and US characteristics remain unclear. We report a case of pancreatic carcinoma in situ discovered based on screening US revealing focal pancreatic parenchymal atrophy. The patient was a male in his sixties. During his hospitalization for lung abscess, US screening revealed focal pancreatic parenchymal atrophy, main pancreatic duct stenosis, and distal pancreatic duct dilatation. There was no interruption of the main pancreatic duct wall or a mass. Therefore, pancreatic carcinoma in situ was suspected. Pancreatic cancer was suspected based on CT, MRI, EUS, and ERCP, and atypical cells were detected at serial pancreatic juice aspiration cytologic examination （SPACE）, so a distal pancreatectomy was performed. The final diagnosis was stage 0 pancreatic carcinoma in situ. It has been reported that focal pancreatic parenchymal atrophy appears earlier than main pancreatic duct dilatation at the stage of carcinoma in situ. An unnatural concave contour on the long-axis view of the pancreas on US can be recognized as focal pancreatic parenchymal atrophy. If this finding can be detected on US during a health checkup, it is expected that many cases of stage 0 pancreatic cancer could be discovered.