小倉 健¹, 増田 大介¹, 井元 章¹, 竹内 利寿¹, 井上 拓也¹, 時岡 聡¹, 栗栖 義賢², 内山 和久³, 梅垣 英次¹, 樋口 和秀¹

Takeshi OGURA¹, Daisuke MASUDA¹, Akira IMOTO¹, Toshihisa TAKEUCHI¹, Takuya INOUE¹, Satoshi TOKIOKA¹, Yoshitaka KURISU², Kazuhisa UCHIYAMA³, Eiji UMEGAKI¹, Kazuhide HIGUCHI¹

¹大阪医科大学附属病院第二内科, ²大阪医科大学附属病院病理学教室, ³大阪医科大学附属病院一般消化器外科

¹Second Department of Internal Medicine, Osaka Medical College, ²Department of Pathology, Osaka Medical College, ³Department of General and Gastroenterological Surgery, Osaka Medical College

キーワード : EUS-FNA, lymphangioma, pancreas, fluid analysis

今回我々は，endoscopic ultrasound-guided fine needle aspiration （EUS-FNA）下の嚢胞液分析が鑑別診断の一助になった稀な嚢胞状後腹膜リンパ管腫の1例を経験したので報告する．症例は40歳，男性．背部痛を主訴に近医を受診，精査の結果，膵嚢胞を指摘されたため，精査加療目的で当科に紹介入院となった．腹部造影CTでは，膵尾部，脾臓，左腎，胃に囲まれた部位に分葉状の造影効果のない嚢胞性病変が認められた．Magnetic resonance cholangiopancreatography （MRCP）では，嚢胞は多房性に描出されたが，主膵管の拡張はなく，主膵管との交通も判然としなかった．十二指腸内視鏡では，粘液の排泄は認められなかった．膵管造影では，粘液を疑う透亮像はなく，また，造影剤の注入圧を上げても嚢胞は描出されなかった．Endoscopic ultrasonography （EUS）では膵尾部に径80 mm大の，大小様々からなる多房性の嚢胞性病変が描出された．以上の画像所見から，intraductal papillary mucinous neoplasm （IPMN）は否定的であり，serous cystic neoplasm （SCN）や，膵仮性嚢胞との鑑別のために嚢胞に対しEUS-FNAを行った．嚢胞内容液は，黄色調であり，CEAは正常範囲内，アミラーゼも161IU/lと軽度高値を示すのみで，粘液性腫瘍や膵仮性嚢胞は否定的であった．有症状であったため，嚢胞摘出術を行った．病理組織学的検討では，腫瘍は大小様々な嚢胞から形成されており，嚢胞壁は，異型を伴わない一層の扁平な上皮からなり，平滑筋成分も認められ，嚢胞状リンパ管腫と診断された．

A case of retroperitoneal cystic lymphangioma in which cystic fluid analysis using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) was helpful for diagnosis is reported. A 40-year-old man was referred and admitted to our department for further examination with a chief complaint of back pain, and detailed examination revealed a pancreatic cyst. Abdominal contrast-enhanced CT showed a non-enhancing, lobulated, cystic lesion surrounded by the pancreatic tail, spleen, left kidney, and stomach. Magnetic resonance cholangiopancreatography showed a multilocular cyst but no dilation of the main pancreatic duct. On duodenoscopy, no mucus excretion was observed. Pancreatography showed no translucency indicative of mucus, and the cyst was not visualized even after increasing the contrast pressure. Endoscopic ultrasound showed a multilocular cystic lesion in the pancreatic tail that was 80 mm in diameter and consisted of loculi of various sizes. No nodes were seen. Intraductal papillary mucinous neoplasm was ruled out based on the above imaging findings, and EUS-FNA was performed on the cyst for differential diagnosis between serous cystic neoplasms and pancreatic pseudocysts. The cystic fluid was yellowish, and based on the findings that CEA was within the normal range and amylase was only slightly elevated (161 IU/l), mucinous tumor and pancreatic pseudocyst were ruled out. Because the patient remained symptomatic, the cyst was removed surgically. Histopathological analysis showed that the tumor consisted of cysts of various sizes. The cyst wall was composed of a single squamous epithelial layer with no atypical cells, and smooth muscle components were also observed. The patient was diagnosed as having cystic lymphangioma.