Gastric Schwannoma Diagnosed by Endoscopic Ultrasonography-Guided Trucut Biopsy
A 72-year-old female was referred for the evaluation of right colon cancer. During staging workup, esophagogastroduodenoscopy showed submucosal elevated lesion with bridging folds located at the greater curvature side of the antrum (). EUS (UM-2000; Olympus, Tokyo, Japan) demonstrated a 40.7×31.7 mm-sized round, hypoechoic mass with internal hyperechogenicity originating from the proper muscle layer (). Abdominal computed tomography scan showed 5×4 cm-sized heterogenous mass located at the greater curvature of the stomach without enlarged lymph nodes (). EUS-TCB with a 19 gauze needle (QuickCore; Wilson-Cook Medical Inc., Winstom-Salem, NC, USA) was performed (). The tissue from the tumor was composed of spindle cells that were only stained with S-100 on immunohistochemistry. Staining for CD 117, CD34, smooth muscle actin, and desmin was negative. These results corresponded with schwannoma of the stomach (). Laparoscopic gastric wedge resection was performed with right hemicolectomy of the colon cancer. There was an intramural solid mass from muscularis propria of the stomach, measuring 5.5×3.5 cm. On section, the cut surface showed a yellowish gray and myxoid appearance (). On immunohistochemistry, diffuse and intense positivity for S-100 protein indicating neurogenic differentiation of the tumor cells was observed. The tumor did not show any expression of CD117, CD34, smooth muscle actin, and desmin, identical with the result of TCB. This suggested that final pathologic diagnosis was also gastric schwannoma.