Endoscopic Ultrasound-Guided Fine Needle Aspiration In The Diagnosis Of Gastrointestinal Stromal Tumours

Introduction:

Gastrointestinal stromal tumours (GISTs) are the most common mesenchymal tumours of the gastrointestinal tract. The accurate diagnosis of GISTs require positive immunohistochemistry staining for c-kit (CD 117) expression, in the setting of an appropriate microscopic appearance of the tumour. Obtaining tumour samples for analysis is therefore critical to diagnosis and subsequent therapy.

We report our experience with the evaluation of 5 cases of suspected GISTs using endoscopic ultrasound guided fine-needle aspiration (EUS-FNA).

Methods:

All patients who were referred to the EUS service at Changi General Hospital, Singapore, between March 2005 and September 2005, for evaluation of a gastric submucosal lesion noted on gastroscopy or a CT scan showing an intra-abdominal mass, subsequently found to have a submucosal tumour arising in the fourth endosonographic layer of the gastrointestinal tract wall and underwent EUS-FNA for histological diagnosis were included in the study. Previous endoscopic biopsies (if any) had been negative for malignancy. Demographic data, EUS appearance of the lesion, cytological and immunohistochemical examinations of EUS-FNA specimens were prospectively collected.

All EUS-FNA specimens were examined immediately by an on-site cytopathologist. Immunoperoxidase stains were performed on cell blocks and/or representative histologic sections of the tumour using commercially available antibodies against c-kit (CD117) and CD34.

Results:

5 patients were diagnosed to have GISTs based on the cytological examination and immunohistochemical staining. Further management of these patients included tyrosine kinase inhibitor (imatinib mesylate) therapy and surgical resection.

Conclusion:

EUS-FNA with immunohistochemistry is a reliable and accurate method in the diagnosis of GIST.