title: Endoscopic ultrasound-guided fine-needle aspiration of metastases to the pancreas: A study of 25 cases.
abstract: BACKGROUND
  Metastases to the pancreas are an uncommon cause of pancreatic masses seen on endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA). The purpose of this study is to retrospectively review the cytomorphology, clinical findings, and results of ancillary studies in a large series of these unusual cases.
  
  
  METHODS
  We searched our institution's pathology database for EUS-guided FNAs of the pancreas that were diagnostic of metastatic tumor over a 5-year period. The final cytologic diagnosis, results of ancillary studies, corresponding histological material, and clinical follow-up data were reviewed in these cases.
  
  
  RESULTS
  A total of 1172 pancreatic EUS-guided FNAs were identified, of which 25 cases (2.1%) had a confirmed diagnosis of a pancreatic metastasis. This included 12 (48%) cases of renal cell carcinoma, 3 (12%) melanomas, 3 (12%) small cell carcinomas, and 7 (28%) other malignancies. In these metastatic tumors involving the pancreas, 20 (80%) of the lesions were solitary. Four (16%) cases had no prior history of malignancy. The average time to diagnosis of pancreatic metastasis was 5.3 years. Immunohistochemistry and special stains were performed in 22 (88%) and 9 (36%) cases, respectively.
  
  
  CONCLUSIONS
  Our data shows that although metastases to the pancreas are rare, they can present as a solitary mass many years after the primary malignancy is diagnosed and can even be the first manifestation of an extrapancreatic primary in a small number of cases. It is important to consider the possibility of a metastatic lesion in the pancreas because this may require a different management than a primary pancreatic tumor.
authors.affiliation: Department of Pathology, University of Pittsburgh Medical Center, S-417 BST, 200 Lothrop Street, Pittsburgh, PA 15261.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Gilbert
authors.forename: Sara E
authors.initials: SE
authors.lastname: Monaco
authors.forename: Scott T
authors.initials: ST
authors.lastname: Cooper
authors.forename: Walid E
authors.initials: WE
authors.lastname: Khalbuss