Endoscopic partial resection with the unroofing technique for reliable tissue diagnosis of upper GI subepithelial tumors originating from the muscularis propria on EUS (with video)

Background

There is a growing body of evidence that a pathological diagnosis is necessary for small (<3 cm in diameter), asymptomatic, hypoechoic, subepithelial tumors (SETs) originating from the muscularis propria on EUS. However, the diagnostic efficacy of current tissue sampling techniques appears to be limited.

Objective

To evaluate the diagnostic yield and safety of endoscopic partial resection using the unroofing technique (EPR-UT) in a subset of patients.

Design

A prospective case series.

Setting

A single tertiary-care referral center.

Patients

Between August 2007 and March 2009, 16 patients with hypoechoic SETs of <3 cm in diameter, originating from the muscularis propria on EUS (14 gastric and 2 esophageal lesions), underwent EPR-UT.

Interventions

The overlying mucosa was removed by using the unroofing technique using a conventional snare with electrical current to expose the tumor sufficiently. Next, the exposed tumor was partially resected by snaring.

Main Outcome Measurements

The diagnostic yield and safety of this method.

Results

EPR-UT provided specimens that were sufficient for a diagnosis and the assessment of risk for malignancy in 15 out of 16 cases (diagnostic yield 93.7% [95% CI, 80.4%-100.0%]). The pathological diagnoses were leiomyoma (7 of 15, 46.6%), GI stromal tumor (6 of 15, 40.0%), aberrant pancreas (1 of 15, 6.6%), and well-differentiated neuroendocrine carcinoma (1 of 15, 6.6%). Six cases with GI stromal tumor were classified as very low risk for malignant potential (mitotic index <5/50 high-power fields). Procedural blood oozing was relatively common (9 of 16, 56.0% [95% CI, 33.0%-77.0%]); however, this minor complication was easily controlled by argon plasma coagulation. There were no procedure-related major complications (0 of 16, 0% [95% CI, 0.0%-23.0%]).

Limitations

Single-center, noncomparative study with small sample size.

Conclusion

EPR-UT appears to be simple, safe, and effective for determining the definite pathological diagnosis and assessing malignant potential of small, hypoechoic SETs originating from the muscularis propria on EUS.

Abbreviations: EPR-UT, endoscopic partial resection using the unroofing technique, EUS-FNA, EUS-guided FNA biopsy, EUS-TCB, EUS-guided trucut biopsy, GIST, GI stromal tumor, HPF, high-power field, IQR, interquartile range, MP, muscularis propria, SET, subepithelial tumor