胆囊隆起性病変の超音波所見と病理学的検討：体外式超音波検査において腫瘍性病変の鑑別が困難であった15 mm以下の病変について

Yasuko Mizushima; 水島 靖子; Rin Yamaguchi; 山口 倫; Masafumi Uchida; 内田 政史; Shinji Uchida; 内田 信治; Michi Morita; 森田 道; Mari Katou; 加藤 真里; Toshirou Yokoyama; 横山 俊朗; Chiyoko Tanamachi; 棚町千代子; Kouji Hashimoto; 橋本 好司; Osamu Nakashima; 中島 収

胆囊隆起性病変の超音波所見と病理学的検討：体外式超音波検査において腫瘍性病変の鑑別が困難であった15 mm以下の病変についてThe Ultrasonographic and Clinicopathologic Study of Polypoid Lesions in the Gall Bladder Measuring 15 mm or Less: The Difficulty in Differentiating Neoplastic Lesions

水島靖子¹，山口倫²，内田政史³，内田信治⁴，森田道²，加藤真里¹，横山俊朗¹，棚町千代子¹，橋本好司⁵，中島収⁵Yasuko Mizushima¹, Rin Yamaguchi², Masafumi Uchida³, Shinji Uchida⁴, Michi Morita², Mari Katou¹, Toshirou Yokoyama¹, Chiyoko Tanamachi¹, Kouji Hashimoto⁵, Osamu Nakashima⁵

¹ 久留米大学医学部附属医療センター臨床検査室Department of Laboratory Medicine, Kurume University Medical Center

² 久留米大学医学部附属医療センター 臨床検査室・病理診断科Department of Pathology and Laboratory Medicine, Kurume University Medical Center

³ 久留米大学医学部附属医療センター放射線科Department of Radiology, Kurume University Medical Center

⁴ 久留米大学病院外科学講座Department of Surgery, Kurume University Hospital

⁵ 久留米大学病院臨床検査部Department of Laboratory Medicine, Kurume University Hospital

受付日：2015年9月18日Received: September 18, 2015

受理日：2016年2月17日Accepted: February 17, 2016

発行日：2016年6月1日Published: June 1, 2016

目的：超音波検査（US）において，胆囊隆起性病変（15 mm以下）の腫瘍性病変（癌・前癌病変）の鑑別は困難な場合が多い．今回，2007年1月から2014年12月までに，術前USで悪性を除外できず，胆囊摘出術を施行した15 mm以下の隆起性病変33例について，腫瘍性病変とさらに胆囊癌の抽出が可能か，病理学的結果からUS所見を検討する．

検討項目：（i）隆起性病変の組織型別分類；（ii）USで有茎性（Ip）・広基性（Is）に分類，腫瘍と非腫瘍におけるUS所見［平均径・部位・表面性状・内部エコー・均一性］と組織像の比較；（iii）Ip・Is周囲の表面隆起（IIa）の有無と組織像，について検討した．

結果：（i）腫瘍13/33例（39%），非腫瘍20/33例（61%）であった．非腫瘍6/20例（30%）は組織学的に慢性胆囊炎であり，次の検討から除外した．（ii）27例における組織学的分布は，Ip型［腫瘍7/17例（41%），非腫瘍10/17例（59%）］で，Is型［腫瘍6/10例（60%），非腫瘍4/10例（40%）］であった．US検討項目の中でIp型病変の表面性状のみ有意差を認め，組織像もそれを反映していた［腫瘍5/7例（71%）が平滑，非腫瘍8/10例（80%）が不整（p＝0.033）］．（iii）IIa病変は2/27例（7%）であったが，Ip・Is癌（各1例）の周囲に存在，主病変と同組織型の癌を認めた．

結語：15 mm以下のIp型腫瘍性病変の鑑別には，表面性状の所見が重要で，IIaの存在は悪性を疑う重要な所見である可能性が示唆された．

Purpose: There are some difficulties in differentiation neoplastic lesions (cancers and precancerous) polypoid lesions measuring 15 mm or less of the gallbladder in ultrasonography (US). We retrospectively examined the US findings by the pathological perspective about the differentiation of the 33 neoplastic lesions and cancers from polypoid lesions measuring 15 mm or less that could not be ruled out to be cancers in the preoperative US, and performed the cholecystectomy from Jan 2007 to Dec 2014.

Method: We investigated; (i) the histology of the polypoid lesions; (ii) the US findings of Ip-type/Is-type (neoplastic and non-neoplastic lesions) [size, the number of cases, position, surfaces, internal echoes, homogeneity] and a comparison between US findings and the pathological findings; (iii) the presence of IIa-type around the Ip-type/Is-type whether or not.

Result: (i) Out of 33 pathological diagnoses, neoplastic lesions were in 13/33 (39%). Non-neoplastic lesions accounted for 20/33 (61%). In the histology, chronic cholecystitis were in 6/20 (30%). Therefore, we omitted them from the following examinations. (ii) The histology of these 27 cases were; Ip-type [neoplastic lesions in 7/17 (41%) vs. non-neoplastic lesions in 10/17 (59%)] and, Is-type [neoplastic lesions in 6/10 (60%) vs. non-neoplastic lesions in 4/10 (40%)]. Among US findings, only the surface of Ip-type was significantly different [neoplastic lesions in 5/7 (71%) were smooth, and non-neoplastic lesions in 8/10 (59%) were irregular (p＝0.033)], and these results were corresponded to the histology. (iii) IIa-types were found in 2/27 (7%), that were Ip-type and Is-type cancers, one each, respectively. IIa-type were both cancers similar to the main lesions.

Conculsion: In Ip-type lesions measuring 15 mm or less, the surface is useful for the differentiation whether neoplastic or not. In addition, the presence of IIa-type lesions is suspected to be a malignant. Therefore, the search for neighboring lesions is important.

Key words: ultrasonography; gallbladder; pathology; polypoid lesion; gallbladder cancer

超音波検査技術

原著Original Article