Solid Pseudopapillary Neoplasm of the Pancreas: EUS Features and Diagnostic Accuracy of EUS-Guided Fine Needle Biopsy Using a 22-Gauge Fork-Tip Needle in a High Volume Center

Background and Aims: Solid pseudopapillary neoplasms (SPN) are rare neoplasms of the pancreatic gland. Despite the indolent behavior, surgical resection is required according to the risk of metastasis development. Few data are available on endoscopic ultrasound (EUS) features, comparison between the features described at EUS and contrast-enhanced, and diagnostic accuracy and safety of EUS-guided FNB in these tumors. Patients and Methods: All consecutive patients with a EUS-guided FNB-based pathological diagnosis of SPN were extrapolated from a prospectively maintained database. Demographic, radiologic, and echo-endoscopic features were collected. FNB specimens were re-evaluated from two expert pathologist and the main histological features of SPN were investigated. Results: Thirty-seven patients were included (32 females and 5 males), with a mean age of 35.8 ± 15.8 years. Contrast-enhanced imaging based diagnosis was accurate in 20 patients (54.1%). EUS features were significantly different compared to contrast-enhanced imaging in terms of cystic appearance (40.5% vs. 16.2%; p = 0.03) and vascular pattern (p = 0.01). FNB-based diagnosis of SPN was confirmed on surgical specimen in all, 37 patients, resulting in a diagnostic accuracy of EUS-guided FNB of 100%. Only one patient (2.6%) experienced a mild procedure-related adverse event. Discussion: Contrast-enhanced imaging based diagnosis of SPN is difficult. Despite the rarity of the disease, EUS-guided FNB with 22-gauge fork-tip needle has a very high diagnostic accuracy for SPN, with rare and mild adverse events.