EUS-guided FNA diagnosis of pancreatic endocrine tumors: new trends identified

Background: Pancreatic endocrine tumors (PETs) are rare (1 per 100,000 population) and are thought to be functioning in up to 85% of cases and are generally less than 2 cm in size. By previous reports, 15% to 50% of PETs are nonfunctioning and are discovered either incidentally or by symptom evaluation from a mass effect. EUS-guided FNA (EUS-FNA) has been shown to accurately diagnose PETs and to localize tumors for surgical resection. Objective: To describe a single-center experience of EUS-FNA diagnosis of PETs and its impact on surgical management. Design: Retrospective cohort study. Setting: University of Pittsburgh Medical Center, Pittsburgh, Pennslyvania. Patients: Patients with PETs diagnosed via EUS-FNA over a 4-year period were identified through the authors' EUS database. Clinical history, laboratory values, diagnostic studies, EUS findings, cytology, pathology, operative records, and surgical pathology records were reviewed. Main Outcome Measurement: Impact of definitive preoperative diagnosis of PET on surgical management. Results: Forty-one patients were diagnosed by EUS-FNA with PET. Thirty-five PETs were nonfunctioning PET; 6 were functioning PET. The mean tumor sizes of functioning and nonfunctioning PETs were 19 mm and 28 mm, respectively. The majority of tumors were located in the pancreatic head. Surgery was performed in 78% of patients; of these, 34% were resected laparoscopipcally. Limitations: Retrospective design and selection bias. Conclusions: In this study, nonfunctioning PETs were more commonly diagnosed compared with functioning PETs. In addition, the PETs were smaller than previously reported, likely because of increasing detection of incidental lesions through widespread use of abdominal imaging.