Endoscopic Ultrasound–Guided Trucut Biopsy of the Cyst Wall for Diagnosing Cystic Pancreatic Tumors

Background & Aims: Nonoperative methods for diagnosis of pancreas cysts often lack sufficient accuracy. Accurate diagnosis is needed to determine prognosis and guide clinical management. The aim of this study was to determine whether the tissue obtained by endoscopic ultrasound–guided trucut biopsy (EUS TCB) is sufficient for histologic diagnosis of cystic pancreatic tumors (CPTs). Methods: EUS TCB was performed in patients with a suspected CPT. A dedicated gastrointestinal pathologist reviewed the core biopsies. The final diagnosis was based on clinical, laboratory, imaging, and biopsy findings, and resected specimens when available. Results: EUS TCB was performed in 10 patients with a suspected CPT. Final diagnoses included serous cystadenoma (SCA, n = 5), islet cell tumor (n = 2), mixed seromucinous lesion (n = 1), polycystic disease of the pancreas (n = 1), and pseudocyst (n = 1). EUS TCB was nondiagnostic in 3 of 10 patients. Among the other 7 patients, TCB diagnosed 4 SCAs, obviating the need for planned surgery in 3 patients. In the fourth patient with an SCA, the TCB result ruled out metastatic disease from locally recurrent lung cancer, allowing a narrowed radiation field. EUS TCB confirmed the need for surgery in 2 patients with an islet cell tumor. In 1 patient, EUS TCB findings were “partially” diagnostic, leading to previously unplanned surgery. Conclusions: This report establishes the capability and safety of EUS TCB to collect sufficient tissue for diagnosing CPTs. The results might help guide clinical management.