Asymptomatic small gastric subepithelial lesions arising from the muscularis propria: outcomes and surveillance in a medical center.

Abstract

Background and aims: Gastric subepithelial lesions (SELs) are frequently identified incidentally during endoscopy, with those originating from the muscularis propria (MP) layer posing diagnostic and management challenges. The optimal surveillance duration for these lesions remains debated. This study aimed to assess size changes in SELs from the MP layer and recommend appropriate surveillance intervals.

Methods: We retrospectively reviewed asymptomatic gastric SELs (≤2 cm) diagnosed via endoscopic ultrasound (EUS) from 2013 to 2018, with follow-up data and no excision within 1 year. Significant progression was defined as a > 20% increase in diameter during EUS surveillance. Lesion-related adverse outcomes, size changes, and histological findings were analyzed.

Results: A total of 561 patients (median surveillance duration: 80 months) were included. One lesion-related adverse outcome (0.2%), liver metastasis from a gastrointestinal stromal tumor, occurred after 62 months. Among the EUS subgroup (n = 313), no differences were observed in progression rates (22.6% vs. 25%) or size increase rates (0.3 mm/year vs. 0.9 mm/year) between micro-SELs (<10 mm) and mini-SELs (10-20 mm). Progressive lesions exhibited faster growth (2.6 mm/year) and more heterogeneous echotexture (43.8%). Most excised lesions were gastrointestinal stromal tumors or leiomyomas.

Conclusions: Over a mean surveillance period of 25.5 months, 13 lesions grew beyond 20 mm. No lesion-related adverse outcomes occurred within the first three years. Histological diagnosis remains the gold standard, but when tissue acquisition is unfeasible, EUS surveillance may be an alternative. Our findings suggest that for asymptomatic micro-SELs (<10 mm) from the MP layer without high-risk features, the surveillance interval can be safely extended to two years.