- 期刊
Endoscopic Ultrasonography in the Diagnosis of Gastric Submucosal Tumor
內視鏡超音波用於胃黏膜下腫瘤之診斷
摘要
傳統內視鏡只能觀察胃壁的黏膜面，因此對於黏膜下腫瘤或來自胃外側的壓迫，無法作正確的診斷。內視鏡超音波可以清楚顯示胃壁的五層構造，除了可分辨胃黏膜下腫瘤與胃外來壓迫外，更可由産生腫瘤的層次及其超音波圖相，推測腫瘤的類別，大小及侵犯程度。馬偕醫院自民國76年10月至80年7月，共有31例因懷疑胃黏膜下腫瘤而接受內視鏡超音波檢查。其中有23例得到組織學診斷或能確定為外來壓迫者，列入此文中之分析。其發生部位由內視鏡超音波正確診斷者為20例(86.9%)。其組織學類別由內視鏡超音波正確診斷者為15例(65.2%)。最常見的胃黏膜下腫瘤為平滑肌（肉）瘤。大都由固有肌層產生，少數源自黏膜肌層。內視鏡超音波下腫瘤呈均勻低迴音或無迴音。但有腫瘤壞死時則呈高低迴音混雜。平滑肌肉瘤一般雖體積較大且較多壞死。在內視鏡超音波下卻無特殊的超音波徵相，可憑以與平滑肌瘤作進一步的鑑別診斷。源出於黏膜下層的腫瘤中，腺肌瘤，類癌及神經纖維瘤的超音波圖相類似異位性胰臟，因此不具診斷的特異性。肌芽細胞瘤(myoblastoma)則呈極強的內迴音，近似脂肪瘤而與Yasuda所報告的低迴音肪瘤而與Yasuda所報告的低迴音不同，一例炎性假性腫瘤在黏膜下層產生高迴音且造成音影，是種極為特殊的發現。胃息肉以內視鏡超音波可確定其病變局限於黏膜層，因此可與黏膜下腫瘤鑑別。胃淋巴瘤及胃硬化癌在傳統內視鏡下，常因黏膜表面變化不明顯，呈現黏膜下腫瘤的外觀而造成兩者間鑑別的困難。在內視鏡超音波中，兩者皆可侵犯胃壁各層，但淋巴瘤較常見為黏膜下層的低迴音腫瘤，且胃壁的分層構造較少破壞。硬化癌則黏膜下層明顯肥厚且呈高迴音，胃壁分層的破壞情況較嚴重。因此，內視鏡超音波對兩者的鑑別診斷甚有助益。至於源自胃部以外的壓迫，如脾腫大或肝癌，以內視鏡超音波不難診斷。 雖然內視鏡超音波無法區別某些腫瘤爲良性或惡性，對一些腫瘤也因超音波圖相不具特異性而無法作組織學診斷，在臨床上懷疑胃黏膜下腫瘤或胃外來壓迫性病變時，內視鏡超音波仍爲很有助益的診斷工具。
並列摘要
Endoscopic ultrasonography (EUS) can display the gastric wall as a 5-layered structure corresponding to its histological layers. It can be used not only in differentiating gastric mural lesions from extragastric compression, also it can be used to delineate the size, location and extent of invasion of the submucosal tumors. From Oct. 1986 through July 1991, there were 31 cases which received EUS examination because of suspected gastric submucosal tumors. Histological diagnoses or documented extrinsic compression could be obtained in 23 cases. Of these, 20 cases (86.9%) were correctly diagnosed as to the origine of lesions but in only 15 cases (65.2%) were the ocrrect histological diagnoses made with EUS. Myogenic tumor is the most common gastric submucosal tumor; also, it is the tumor most frequently associated with reliable ultrasonic signs for histological diagnosis. Lymphoma & scirrhous carcinoma are other tumors in which EUS may make correct histological diagnosis but EUS tends to miss the subtle change of mucosa and thus may underestimate the extent of invasion. Although EUS is limited by lacking of specificity in differentiating between benign and malignant lesions and in making histological diagnoses of several kinds of submucosal tumors, it is still a useful tool when a suspected gastric submucosal tumor or a suspected extragastric compression is encountered.