Impact of Tumor Type and Size on Macroscopic Tissue Core Retrieval in Endoscopic Ultrasound-guided Fine Needle Biopsy for Pancreatic Malignancies

Endoscopic ultrasonography (EUS) is pivotal for diagnosing and sampling pancreatic tumor tissues. This study aimed to assess how the histological type and size of tumors influence the adequacy of macroscopic tissue cores acquired using EUS-guided fine needle biopsy (FNB). We conducted a retrospective study involving 180 patients with pathologically confirmed pancreatic malignancies at our hospital, a medical center, between July 2020 and June 2023. Personal and clinical data, EUS findings, and pathological results were extracted from the patient records. The macroscopic tissue core acquisition rate was 86.1%. Patients with tumors larger than 3 cm had a higher sufficiency rate (93.3%) compared to those with tumors 3 cm or smaller (78.9%, p = 0.005). It was more difficult to obtain sufficient tissue cores from neuroendocrine tumors than from adenocarcinomas (67.7% vs. 89.9%, p = 0.001). Interestingly, obtaining a sufficient tissue core only affected the diagnostic rate of adenocarcinoma (93.3% vs. 60%, p < 0.001) but did not significantly influence the diagnostic rate of neuroendocrine tumors. This study highlights that small tumors (< 3 cm) and neuroendocrine tumors pose a challenge in obtaining sufficient tissue cores. However, obtaining sufficient tissue cores significantly influences the pathological diagnosis of FNB in adenocarcinoma but not in neuroendocrine tumors.