STUDY AIM

To assess the accuracy of ultrasound-guided fine-needle aspiration biopsy in the differential diagnosis of gastrointestinal stroma cell tumors (GIST) from other submucosal tumors, using both cytology and histology.

PATIENTS AND METHODS

We conducted a prospective study from May 2005 to September 2008 in all patients presenting with upper gastrointestinal submucosal tumors. Only patients in whom surgical resection was carried out were included in the final analysis. In cases of mesenchymal tumor, immunocytochemistry was attempted for further differentiation between GIST and non-GIST. Surgical histopathology served as the gold standard.

RESULTS

A total of 47 patients were analyzable, with a final histologic diagnosis of 35 mesenchymal tumors. Sufficient tissue for conventional cytologic diagnosis was obtained only in the 35 patients with mesenchymal tumors; in this subgroup, immunocytochemistry was possible in 46 %. If and only if enough material was available for immunocytochemistry, the sensitivity for (correct recognition of) GIST tumors was 93 %. In all 12 patients with nonmesenchymal tumors and lesions, cytology was nondiagnostic and the diagnosis had to be based on clinical suspicion and the appearance on endoscopy and endoscopic ultrasound (EUS). On an intention-to-diagnose basis, endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) had a positive predictive value for mesenchymal tumors of 100 %, but no value for the diagnosis of other lesions; using immunocytochemistry, a GIST tumor was recognized among the mesenchymal tumors with a sensitivity of 58 % and a specificity of 8 %.

CONCLUSIONS

EUS-FNA-based cytology is safe and has only limited value for the differential diagnosis of submucosal tumors, mainly because insufficient material is harvested. Better tissue acquisition techniques are necessary for better differential diagnosis.