Usefulness of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) for undiagnosed intra-abdominal lymphadenopathy

Background: The differentiation between benign and malignant abdominal lymph nodes is difficult, especially if no primary site is evident or if cancer resection was remote in time. The aim of this study was to evaluate the yield of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in patients with undiagnosed intra-abdominal lymphadenopathy. Methods: Fifty-seven consecutive patients with undiagnosed abdominal lymphadenopathy who were registered in our EUS-FNA database from January 1997 to December 2007 were reviewed. EUS-FNA was carried out using a 22-G needle. The final pathological diagnosis was based on the cytopathological, histological, and immunohistochemical (IHC) findings. Results: Adequate specimens were obtained in 93% cases. The final diagnoses included local recurrence of malignancy after resection (n = 16), lymphoma (n = 12), and benign/reactive changes (n = 17). The sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of EUS-FNA were 94, 100, 100, 90 and 96%, respectively. In addition, it was also possible to classify lymphoma subtypes in 83% of cases. No complications occurred during the procedures. Conclusions: EUS-FNA is clinically very useful for establishing the diagnosis of abdominal lymphadenopathy of unknown cause and can provide sufficient tissue for IHC and subtyping of lymphomas.