Prospective Comparison of Endoscopic Ultrasound-Guided Fine Needle Aspiration (EUS-FNA) and Surgical Histology in Upper Gastrointestinal Submucosal Tumors

Abstract

Background: To assess the accuracy of EUS-FNA in the diagnosis of gastrointestinal submucosal tumors we compared the results of the cytological and immunocytochemical FNA-results with the final histological results upon surgery. Patients and Methods: We conducted a prospective duocenter study and enrolled 47 patients from June 2005 until October 2007 that presented with submucosal GI tumors. Eligible patients were examined with the radial scanner (Olympus - GF-UE160-AL5) for nodules arising within the esophageal, gastric, or duodenal wall layers. After obtaining the written informed consent EUS-FNA (19-22 G needles) was performed (Olympus GF-UCT140-AL5). All aspirates were reviewed by a specialized cytopathologist for stroma tumor cells and reactivity for CD117 (C-kit) and CD34 immunostaining. For reference, endoscopic or surgical resection with histological examination was performed. Results: We enrolled 47 patients with submucosal tumors of the upper gastrointestinal tract. 42 patients were resected (10 esophageal, 29 gastral, 3 duodenal). The final histological results revealed 22 GISTs, 11 leiomyomas, 1 brunneroma, 1 hamartous cyst, 1 ectopic pancreas, 1 granulosa cell tumor, 1 bronchogenic cyst, 1 hamartom, 2 lipomas and 1 accessory spleen. 5 Patients refused surgery and were followed-up clinically. Only 4 submucosal tumors were resected endoscopically (2 leiomyomas, 1 lipoma and 1 bronchogenic cyst) and all GISTs were removed surgically. All GISTs were identified in the stomach and could be easily accessed by EUS-FNA. In 8 of 22 patients (36%) we could not obtain sufficient cellular tissue for further immunocytochemical analysis. Surprisingly, this sampling problem was unrelated to tumor size: the average size of GISTs with enough cells for immunocytochemical analysis was 37 mm versus 42 mm in those with less cellular material. All GISTs providing a sufficient number of cells were correctly identified as mesenchymal tumors, no false positive diagnosis occurred. Sensitivity, specificity, positive and negative predictive value of EUS-FNA was 100% each. Only 1/13 GISTs was not correctly classified by immunocytochemistry (typing accuracy 92,3%). No serious adverse events related to the fine needle aspiration were reported. Conclusions: EUS-FNA is highly accurate for diagnosis and management of submucosal gastrointestinal tumors in the upper GI tract and reveals no adverse events. One remaining problem is the frequency of suboptimal aspirates for further immunocytochemical analyses. However, this problem may be overcome either by dedicated new needles, a stand-by cytopathologist, or a bed-side automated characterization of the specimen quality.