内視鏡下超音波像からみた粘膜下腫瘍様の食道表在癌の特徴

Ultrasonographic Characteristics of Submucosal Tumor-like Superficial Esophageal Cancer during Endoscopy

要旨　当科の食道表在癌切除例132例中，粘膜下腫瘍様の形態を呈した食道表在癌9例の内視鏡下超音波画像の特徴について検討した．組織型は扁平上皮癌と特殊型の食道癌で，全例sm癌であった．表面性状から診断する内視鏡に対して，高周波数細径超音波プローブは食道壁表層の描出に優れ，病変の詳細な断層像を見ることができる．腫瘍は第2～4層に連続する不整形で境界不鮮明な充実性の低エコー腫瘤として描出された．mmを表す第3層は腫瘍辺縁部で中断していた．分葉した形態を示すことが多く，1つ1つの塊の大きさは不揃いなのが特徴であった．第4層深部と第5層はいずれの症例でも保たれsm癌と正診できていた．鑑別すべき疾患には良性のSMTのほかに，癌周囲に生じる細胞浸潤やリンパ濾胞過形成，血管，食道腺などがある．層構造の連続性，腫瘍のエコーレベル，形態と大きさに着目して検索することが重要と考えられた．

　Of 132 cases with superficial esophageal cancer who underwent resection in our department, 9 cases had submucosal tumor-like superficial cancer, and their ultrasonographic characteristics during endoscopy were examined. Histological types of these cancers were squamous cell carcinoma and specific esophageal cancer, both of which are sm cancer. While endoscopy examines superficial conditions of the esophagus, a thin high frequency ultrasonic probe can image the superficial layer of the esophageal wall and shows tomographic images of lesions in detail. The tumor in these cases was imaged as part of the tissues showing low echoes, which was irregular in shape, solid without clear outline and present continuously in the second to the fourth layers. The third layer, which is in the order of mm, was discontinued in the periphery of the tumor. The deep regions of the fourth layer and fifth layer were maintained in all the cases, and the tumor had been accurately diagnosed as sm cancer. Diseases to be distinguished are benign SMT, and cellular infiltration, hyper plasia with formation of lymphatic follicles blood vessels and esophageal glands around the tumor. It is important for diagnosis to examine the continuity of layer structures, echo level of the tumor, and shape and size.