A Subepithelial Tumor With Surface Changes Removed by Endoscopic Submucosal Dissection

QuestionA 60-year-old man presented with gastric subepithelial tumor with surface changes.A soft subepithelial tumor, measuring approximately 20 mm, was observed on the lesser curvature of the gastric lower body.A whitish color change and depression was seen on its surface (Fig. 1).On endoscopic ultrasonography, the lesion was homogenous, anechoic, and confined to the submucosal layer.Mucosal thickening was observed above it (Fig. 2).What is the most likely diagnosis? AnswerA forceps biopsy was performed at the whitish color-changed and depressed area on the lesion's surface, which revealed tubular adenoma with low-grade dysplasia.Endoscopic submucosal dissection (ESD) was performed for complete removal and histologic confirmation of the underlying pathology.After marking the area around the villous change on the tumor surface (Fig. 3A), a 0.9% saline solution with epinephrine and indigo carmine was injected into the submucosal layer (Fig. 3B).After circumferential mucosal incision (Fig. 3C), submucosal dissection was performed with an insulated-tipped knife (Fig. 3D).A cystic lesion with fibrotic tissue was observed below the submucosal injection fluid (Fig. 3E).En-bloc resection of the tumor was safely performed (Figs.3F and 4).Histopathologic examination revealed a cystically dilated glandular structure extending into the submucosal layer with surrounding fibrotic and inflammatory changes, consistent with gastritis cystica profunda (GCP), and an overlying well-demarcated tubular adenoma with low-grade dysplasia (Fig. 5).The patient was discharged two days after ESD without any complications.GCP is caused by chronic inflammation, ischemia, and foreign body reaction.1,2 Because of this long-standing stimulation, GCP often shows surface mucosal changes, and several reports have described the development of adenoma or early gastric cancer on its surface.3,4 In the present case, ESD was safely performed for a lesion with such surface changes, leading to complete resection and histologic diagnosis.Although GCP itself is a benign condition, its potential association with epithelial dysplasia or carcinoma highlights the importance of careful endoscopic evaluation.Recognizing subtle mucosal alterations overlying a subepithelial lesion may allow earlier detec-