[350] Fine Needle Aspiration of Pancreatic Endocrine Neoplasm (PEN): An 18-Year Retrospective Study of 134 Cases.

Shaoxiong Chen, Narasimhan Agaram, John M Dewitt, Rosen Dimitrov, Robert Emerson, Rebecca Marks, Xiaoyan Wang, Howard Wu, Harvey Cramer. Indiana University, Indianapolis

Background: PENs are relatively uncommon, accounting for 2-4% of all clinically detected pancreatic neoplasms and the long-term survival for these patients is much better than for patients with carcinomas of the exocrine pancreas. The preoperative diagnosis of PEN by FNA assists the surgeon in therapeutic decision-making.
Design: A search of our laboratory information system was performed from July 1992 through June 2010 to identify all cytology and surgical pathology cases. Patients with multiple endocrine neoplasia (MEN I) were excluded. Slides from cases with discrepancies between the cytologic and histologic diagnoses were re-examined.
Results: A total of 134 PEN cases diagnosed by FNA were collected over an 18-year period. The age of the patients ranged from 21 to 95 years with a mean age of 59 years. The male to female ratio was 1.3:1. The size of PEN ranged from 0.5 to 11.2 cm with a mean size of 3.2 cm. Fifteen cases had liver metastasis, 9 had lymph node metastasis and 5 had both liver and lymph node metastasis. Fifteen PEN cases were cystic lesions (11%), while 119 cases were solid lesions (89%). The FNA diagnoses were classified as follows: PEN (103 cases, 77%), suggestive of PEN (16 cases, 12%), no atypical cells identified (4 cases, 3%), non-diagnostic (7 cases, 5%), and other diagnoses (4 cases, 3%). Histologic correlation was available for a total of 78 FNA cases (58%). Among 56 cases diagnosed as PEN by FNA, 54 cases (96%) were confirmed histologically; the remaining 2 cases showed poorly differentiated adenocarcinoma with focal neuroendocrine features in one and no tumor in the other. Follow-up of the 9 cases diagnosed as suggestive of PEN by FNA, included 3 cases of PEN, 2 cases of chronic pancreatitis, 2 cases of ductal adenocarcinoma, 1 case of PEN vs solid-pseudopapillary tumor (SPPT), and 1 case of SPPT. There were 4 cases diagnosed as 'no atypical cells' and the 5 nondiagnostic cases that were proven to be PEN histologically. Finally, 4 other cases classified by FNA as adenocarcinoma (2), suggestive of carcinoma (1), and SPPT (1), respectively were diagnosed as PEN by histology.
Conclusions: Overall, 54 of the 70 histologically confirmed PEN cases (76%) were diagnosed correctly by preoperative FNA. The false negative rate, attributable to specimen hypocellularity and sampling error, was within acceptable limits (7%). Diagnostic pitfalls included SPPT, chronic pancreatitis and ductal adenocarcinoma. Despite its limitations, FNA of PEN remains a clinically useful procedure.
Category: Cytopathology

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 71, Tuesday Morning


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