EUS-guided sampling of suspected GI stromal tumors

BackgroundThe diagnostic yield of EUS-guided FNA (EUS-FNA) of suspected GI stromal tumors (GIST) has not been assessed in large series.ObjectiveOur purpose was to determine the diagnostic yield of EUS-FNA of subepithelial lesions with EUS features suggestive of GIST.DesignRetrospective database review.SettingTertiary care referral center and an urban Veterans Administration hospital.PatientsConsecutive patients referred for EUS evaluation of upper GI subepithelial lesions of the fourth endosonographic layer who underwent EUS-FNA.Main Outcome MeasurementsProportion of patients whose cytopathologic examination was diagnostic (immunohistochemical stains establish a specific diagnosis), suspicious (spindle cells identified, quantity not sufficient for specific stains), or nondiagnostic.ResultsA total of 112 patients (45.5% female, mean age 61.6 years) underwent EUS-FNA (mean number of FNA passes 5.3). Tumor location was as follows: stomach 62.5%, esophagus 30.4%, and duodenum 7.1%. EUS-FNA was diagnostic in 61.6%, suspicious (spindle cells) in 22.3%, and nondiagnostic in 16.1%. The histologic results were 31.3% GIST, 26.8% leiomyomas, 22.3% spindle cell neoplasms, 3.5 % neural tumors, and 16.1% nondiagnostic. Fifteen (12.5%) patients also underwent EUS-guided core needle biopsy needle sampling; 7 were diagnostic, 2 suspicious, and 6 nondiagnostic. Twenty-four (20.0%) patients underwent jumbo forceps sampling; 5 were diagnostic, 1 suspicious, and 18 nondiagnostic. There were no cases of diagnostic core needle biopsy after nondiagnostic FNA core needle biopsy. Jumbo forceps biopsy of ulcerated masses was diagnostic in 3 GISTs in which FNA was nondiagnostic. Univariate and multivariate analyses showed that no variable was associated with an increased diagnostic yield.ConclusionsEUS-FNA sampling of subepithelial lesions was diagnostic in 61.6% and showed a spindle cell neoplasm (“suspicious”) in another 22.3% (diagnostic yield 83.9%). Core needle biopsy needle sampling did not increase the yield, but in the setting of an ulcerated mass, forceps biopsy may be diagnostic.