Abstract
Endoscopic ultrasonography (EUS) was performed in 71 patients, and the findings were compared with the macroscopical and histological findings. Submucosal tumors were treated in 32 patients surgically (n=27) or endoscopically (n=5). Histological diagnosis was made on 71 lesions from surgically or endoscopically resected specimens, or bioptic specimens (n=39). Tumor size, tumor shape, growth pattern of the tumors were compared with EUS findings and macroscopical findings. Internal echo pattern and histological findings were compared, retrospectively. EUS measurement of the tumor size was made in two directions, length-and-height or width-and-height. EUS data were almost identical to actual measurement from the resected tumors, and the error was less than 10mm. Tumor shape was correctly diagnosed by EUS in 27 of 32 lesions. Tumor growth pattern was classified in correlation with 4th layer of EUS or muncular layer, and EUS diagnosis of growth pattern was correct in 26 of 32 lesions. Internal echo patterns, classified into 5 types were compared with the histological findings. Eighty-seven percent of submucosal tumors (SMT) with "hypoechoic" pattern were leiomyoma. Fifty percent of the tumor with "mixed irregular" echo pattern were malignant. Single criteria derived from EUS findings, such as tumor size, tumor, shape or growth pattern of the tumor can not lead to an accurate diagnosis of malignant SMT, when analyzed retrospectively. To improve the diagnostic accuracy of EUS in differentiating malignant tumors, such as leiomyosarcoma or leiomyoblastoma, we postulate "malignant sign (MS)" from the combination of EUS findings. When MS assigned to 1) tumor larger than 20mm, with intermediate or mixed irregular echo pattern, or 2) tumor larger than 40mm, with hypoechoic pattern, 12 lesions were true positive and 49 true negative. False positive and false negative case were 1 and 12, respectively. Sensitivity of MS in diagnosis of malignant tumors was 92% and the specificity was 84%. EUS diagnosis of SMT was accurate in measuring its size, shape and growth pattern. Internal echo pattern reflects its internal structure. MS derived from the combination of tumor size and internal echo pattern is highly sensitive and specific in the diagnosis of malignant SMT.
