Utility of endoscopic ultrasound‐guided fine‐needle aspiration cytology in rapid on‐site evaluation for the diagnosis of gastric submucosal tumors: Retrospective analysis of a single‐center experience

BACKGROUND: Recently, there have been reports of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) cytology being used for the diagnosis of various kinds of tumors. This method has also been adopted in the diagnosis of gastric submucosal tumors (SMTs). The aim of this study was to analyze the utility of EUS-FNA cytological examination in rapid on-site evaluation (ROSE) for gastric SMTs. METHODS: Retrospective analyses of the cytological specimens of EUS-FNA in ROSE for gastric SMTs and determination of the diagnostic accuracy of EUS-FNA combined with immunohistochemical analysis of cell blocks and surgically resected specimens were performed. RESULTS: A total of 110 patients were enrolled in this study. The most common cytodiagnosis was spindle cell tumor (62 patients, 55.5%), followed by negative for tumor (34 patients), and malignant lymphoma and adenocarcinoma (five patients each). Cell blocks were prepared for 60 of the patients (96.8%), cytologically diagnosed with spindle cell tumor. Immunohistochemical analyses using cell block revealed gastrointestinal stromal tumor (GIST, c-kit+ /desmin- , 49 patients) and leiomyoma (desmin+ /c-kit- , five patients). Thus, using EUS-FNA specimens, 83.1% of GIST patients were pre-operatively diagnosed. CONCLUSIONS: EUS-FNA cytological examination in ROSE for gastric SMTs aided in the collection of sufficient amounts of tumor tissues for preparing cell blocks. This method led to a high rate of accurate pre-operative diagnosis in patients with gastric SMTs.