Frequency of occurrence and characteristics of primary pancreatic lymphoma during endoscopic ultrasound guided fine needle aspiration: a retrospective study.

BACKGROUND Primary pancreatic lymphoma is a rare tumour of the pancreas. Data on the role of endoscopic ultrasound guided fine needle aspiration for its diagnosis are scant. AIM To identify the frequency of occurrence, sonographic characteristics and cytological findings that are predictive of primary pancreatic lymphoma. METHODS Pancreatic lymphoma cases were identified by retrospective review of solid pancreatic masses over 10-year period. RESULTS 12/2397 (0.5%) lesions were identified. Patients were predominantly white (92%) and male (58%). Mean largest dimension was 47.5mm and 83.3% were located in the head. The mass appeared heterogeneous in 75% and peripancreatic lymphadenopathy was noted in 58%. None of the patients showed features of chronic pancreatitis or pancreatic ductal dilation. Rapid onsite analysis revealed atypical lymphocytes in 92%. Flow cytometry confirmed diagnosis in 75% of cases. CONCLUSIONS Primary pancreatic lymphoma is encountered in 0.5% of patients undergoing endoscopic ultrasound guided fine needle aspiration. A large heterogeneous mass, in the absence of chronic pancreatitis or pancreatic duct dilation that reveals atypical lymphocytes on fine needle aspiration is suggestive.