Leiomyoma is more common than expected among gastric gastrointestinal stromal tumors (GISTs) measuring 2 cm or less in diameter, a new study published in the Journal of Gastroenterology and Hematology found.

Tissue diagnosis with an effective and safe sampling technique like an endoscopic incisional biopsy is needed to make further clinical decisions, the authors said.

To analyze the clinical and pathologic features of small gastric GISTs measuring 2 cm or less in diameter and to evaluate the safety and efficacy of endoscopic incisional biopsy for these tumors, a team of researchers led by Tsu-Yao Cheng from the National Taiwan University Cancer Center in Tapei conducted a prospective study of 70 patients with suspected gastric GISTs based on endoscopic ultrasound.

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The researchers first recruited 30 patients to evaluate the safety and efficacy of endoscopic incisional biopsy. They then recruited 40 patients and randomly assigned them to either receive endoscopic incisional biopsy or bite-on-bite biopsy to compare the diagnostic yield, procedure time, and rate of adverse events between the 2 approaches.

The results showed that in patients who received endoscopic incisional biopsy, the diagnostic rate was 94%. Leiomyoma was diagnosed in 74% of cases. This was almost 3 times as much as GIST, diagnosed in 26% of cases.

In half of the small gastric GISTs, there was a mutation in the KIT protooncogene, and in 16% of cases, there was a mutation in exon 12 of the PDGFRA gene.

The diagnostic yield of endoscopic incisional biopsy was 85% while that of bite-on-bite biopsy was 50%. There was no statistically significant difference between the 2 techniques in terms of procedure time or rate of adverse events.


Wong SJ, Wang HP, Shun CT, et al. Tissue diagnosis necessary for small endoscopic ultrasound-suspected gastric gastrointestinal stromal tumors 2 cm or less in size: a prospective study focusing on the endoscopic incisional biopsy. J Gastroenterol Hepatol. Published online May 2, 2022. doi:10.1111/jgh.15876