Endoscopic guess of SMT histology is very difficult. I recommended surgery under the impression of GIST. But, the surgic pathology was like this.
Stomach, mid body, anterior wall, wedge resection : Schwannoma
Actin (Smooth muscle) : Negative in tumor cells
Desmin : Negative in tumor cells
DOG-1 : Negative in tumor cells
S-100 : Positive in tumor cells
Ki-67 : Positive in 5-10% of tumor cells
C-KIT (CD 117) : Negative in tumor cells
Differential diagnosis between GIST and schwannoma is very difficult. In this case, the radiologic differential diagnosis was "1) GIST, 2) neurogenic tumor".
Followings are all schwannomas.