Follow-up Results of Benign-Appearing Submucosal Tumor by EUS

Back ground/Aims: EUS has been used for differential diagnosis between benign and malignant submucosal tumor. However, the natural course of benign-appearing submucosal tumor is not clearly elucidated. The aim of this study was to evaluate the natural course of benign-appearing submucosal tumor in EUS in gastrointestinal tract. Methods: We evaluated retrospectively the changes of size, internal echo pattern and marginal regularity in 38 patients who had benign-appearing submucosal tumor more than 1cm and less than 3cm and followed up for more than 1 year. We regarded an increase or a decrease of over 25% in maximal diameter as significant size change. Results: Diagnosis of initial EUS were 19 leiomyoma/GIST, 4 lymphangioma, 6 lipoma, 6 ectopic pancrea, 1 granuloma and 1 hemangioma. Submucosal tumors from the following areas: esophagus 14, stomach 19, duodenum 1 and colon 3. The average size of tumors was 16.9mm. The mean follow-up period was 35.6 months (range 12–94 months). Followed-up revealed no change in echo pattern and size in 69 of 71 patients (94.6%). In one patient, homogenous hypoechoic tumor suggesting gastric leiomyoma increased from 26 to 34mm without the change of internal echo or marginal regularity at surveillance of 24 months, revealing leiomyoma after laparoscopic gastric wedge resection. In the other patients, a 20mm-sized homogenous anechoic lesion with thin septation in initial EUS increased a 30mm-sized anechoic lesion without the change of internal echo or marginal regularity at surveillance of 26 months, revealing cystic lymphangioma by EUS-guided FNA. Conclusion: Most benign-appearing submucosal tumors more than 1cm but less than 3cm by EUS was not changed during a period of 12 months and EUS criteria are effective to conclude to benign submucosal tumors. Benign-appearing submucosal tumors in EUS might be followed at interval of 1 year by EUS.