隆起型食道腫瘍の鑑別診断―X線を中心に

Radiographic Diagnosis of Protruding-type Esophageal Tumors

要旨　粘膜下腫瘍様もしくは特殊な組織型を呈する食道の表在型悪性腫瘍と良性疾患のX線所見について，提示可能な自験例の画像所見と報告例からみた特徴について概説した．悪性腫瘍：（1）典型的な組織像を呈する類基底細胞（扁平上皮）癌は，一見粘膜下腫瘍様であったが，立ち上がりは急峻で表面にゴツゴツした凹凸を伴っていた．（2）lymphoid stromaを伴う扁平上皮癌や内分泌細胞癌は，表面平滑な0-Is型であったが，表面に不整形の陥凹を伴っていた．（3）癌肉腫は，亜有茎性でポリープ状の粗大な楕円形隆起を呈した．良性腫瘍：（1）平滑筋腫は，表面陥凹を伴わない半球状の平滑な粘膜下腫瘍や大小の平滑な結節状隆起を呈したが，（2）10mm以上の顆粒細胞腫は表面に溝状，切れ込み状の陥凹を伴っていた．（3）海綿状血管腫は2コブ状で表面平滑な軟らかく丈の低い粘膜下腫瘍であった．（4）報告例も含めた膿原性肉芽腫は亜有茎性～有茎性のポリープ状隆起で棍棒状から分葉状を呈していた．（5）炎症性線維性ポリープは下部食道に発生した長い茎を有する上皮に覆われた大きなポリープであった．隆起型の食道病変はまれな疾患が多く，画像所見のみによる質的な鑑別は困難であるが，表面のわずかな凹凸や陥凹から癌の所見を見い出すことや，報告例の形態的特徴やパターンを十分記憶して念頭に置くことが，術前の質的診断の向上に寄与すると思われた．

　We summarize the characteristic radiographic findings of superficial malignant tumors presenting as submucosal tumor-like or special histological type and benign tumors on image findings in our representative cases and reported cases. Malignant tumor :（1）Although basaloid（squamous epithelium）cancer presenting with a typical histological picture initially had a submucosal tumorous appearance, the initial rise was precipitous, and the surface was rough and bumpy.（2）Epidermoid cancer accompanying lymphoid stroma and endocrine cell cancer was 0-1s types with smooth surfaces having irregular recesses.（3）Cancerous sarcoma was subpedunculated, polypoid, rough, and large, with oval protuberances. Benign tumors :（1）Leiomyoma presented as hemispheroid and smooth submucosal tumors without surface recesses, and small and large, smooth, and nodular protuberances.（2）Granular cell tumors≧10mm in diameter were accompanied by canaliform and slit-shaped recesses on the surface.（3）Cavernous hemangioma appeared as double bunchy, soft, and low submucosal tumors with a smooth surface.（4）Purulent granuloma, including reported cases, was subpedunculated-pedunculated polypoid protuberances presenting a claviform and lobulated form.（5）Inflammatory fibroid polyps were large polyps covered by epithelium, with a long pedicle originating in the lower esophagus. Esophageal lesions of prominent type are rare and its qualitative discrimination only by imaging findings is difficult. We consider that it will contribute to improved preoperative qualitative diagnosis to detect cancer findings from slight convexoconcavities and recesses on the surface and be sufficiently aware of morphological characteristics and patterns in reported cases.