A Triple Approach for Diagnostic Assessment of Endoscopic Ultrasound-Guided Fine Needle Aspiration in Pancreatic Solid Masses and Lymph Nodes

Endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) has been becoming the standard tool for acquiring pancreatic lesion tissue. However, a single cytologic or histologic evaluation is not satisfactory for diagnosis. In this study, we evaluated the diagnostic yield of EUS-FNA for pancreatic solid masses and intra-abdominal lymph nodes using a triple approach. This study included patients undergoing evaluation for a solid pancreatic mass (n = 59) or intra-abdominal lymph nodes (n = 16) using EUS-FNA with a 22- or 25-gauge (G) needle, respectively. The specimens from each pass were analyzed by on-site cytology using Diff-Quick stain, cytology using Papanicolaou stain, and histology with immunohistochemical (IHC) staining. A total of 75 patients (49 males; mean age; 63.7 years) were included. The median number of needle pass for diagnosis of malignancy was 2.0, and there was no technical failure. The diagnostic accuracies with on-site cytology, cytology using Papanicolaou staining, and histology were 70.7, 80.0, and 80.0 %, respectively. The diagnostic accuracy using a triple approach was significantly greater than cytology using Papanicolaou staining alone (94.7 vs. 80.0 %; p = 0.007). In patients with malignant lesions, cytology identified 12 of 71 (16.9 %) malignant lesions that were not diagnosed by histology using IHC, and histology identified six (8.5 %) malignant lesions that were not diagnosed by cytology. On-site cytopathologic evaluation combined with cytologic and histologic analysis with IHC stain for one-pass specimen is considered to be able to increase the overall accuracy of EUS-FNA in pancreatic solid masses and lymph nodes.