田井 由実¹, 丸上 永晃², 丸上 亜希², 平井 都始子², 野見 武男³, 庄 雅之³, 高野 将人⁵, 大林 千穂⁴, 吉川 公彦¹

Yumi TAI¹, Nagaaki MARUGAMI², Aki MARUGAMI², Toshiko HIRAI², Takeo NOMI³, Masayuki SHO³, Masato TAKANO⁵, Chiho OHBAYASHI⁴, Kimihiko KICHIKAWA¹

¹奈良県立医科大学付属病院放射線・核医学科, ²奈良県立医科大学付属病院総合画像診断センター, ³奈良県立医科大学付属病院消化器・総合外科, ⁴奈良県立医科大学付属病院病理診断科, ⁵市立奈良病院病理診断科

¹Department of Radiology and Nuclear Medicine, Nara Medical University, ²Department of General Diagnostic Imaging Center, Nara Medical University, ³Department of Surgery, Nara Medical University, ⁴Department of Diagnostic Pathology, Nara Medical University, ⁵Department of Diagnostic Pathology, Nara City Hospital

キーワード : gallbladder cancer, adenosquamous cell carcinoma, papillary adenocarcinoma, contrast-enhanced ultrasonography, Sonazoid

症例は70代女性．前医の腹部超音波検査で胆嚢癌が疑われ，当院消化器外科に紹介となった．当院の超音波検査では分節型の胆嚢腺筋腫症と胆嚢結石を背景に，底部にやや不均一な高エコーを示す約28 mmの不整な結節状の隆起性病変と，その近傍に均一な低エコーを示す偏在性の壁肥厚性病変を認めた．いずれも境界は比較的明瞭であった．Sonazoid造影超音波検査では前者は動脈相早期より強く濃染し，病変内に樹枝状の血管像を認めたのに対し，後者は緩徐でやや弱い造影効果を示し，内部にはまばらな線状の血管構築像を認めた．胆嚢癌として胆嚢摘出術・肝床切除術・リンパ節廓清術が施行された．病理学的にAdenosquamous cell carcinoma with foci of well to moderately differentiated papillary adenocarcinoma と最終診断され，超音波検査で認めた不整隆起性病変は乳頭腺癌，壁肥厚性病変は腺扁平上皮癌に相当していた．特に腺扁平上皮癌部分には，乳頭腺癌と比較して豊富な線維性間質の増生と毛細血管数減少がみられ，造影超音波所見の違いに寄与したものと考えられた．異なる組織の胆嚢癌における血管構築像の違いを造影超音波で描出し得た貴重な症例であった．

A female in her 70s was admitted to our hospital because of suspected gallbladder carcinoma on abdominal ultrasonography (US) performed by her previous doctor. US showed an approximately 28-mm mild hyperechoic irregular mass and hypoechoic wall thickening at the fundus of the gallbladder. On contrast-enhanced ultrasonography (CEUS), the irregular mass was enhanced rapidly and vividly, and the wall thickening was enhanced slowly and progressively in the arterial phase. CEUS also showed branched blood vessels in the irregular mass and sparse linear blood vessels in the thickened wall. Cholecystectomy, gallbladder bed resection, and lymphadenectomy were performed. The diagnosis was adenosquamous cell carcinoma with foci of well to moderately differentiated papillary adenocarcinoma. The irregular mass and the wall thickening pathologically corresponded to papillary adenocarcinoma and adenosquamous cell carcinoma, respectively. The adenosquamous cell carcinoma showed subserosal invasion with a strong desmoplastic reaction in the stroma. It is suggested that abundant fibrotic stroma and a decrease in capillary blood vessels could have caused the difference in intralesional blood vessel pattern depicted on CEUS between the adenosquamous cell carcinoma and the papillary adenocarcinoma of the gallbladder.