[680] Follow-Up of Pancreatic Fine Needle Aspirates Diagnosed as Atypical: A Retrospective 15-Year Review of 127 Cases

MF Varsegi, HM Cramer. Indiana University, Indianapolis, IN

Background: Since a false-positive pancreatic FNA can lead to unnecessary radical surgery, the atypical diagnostic category may be employed whenever the cytopathologist lacks complete confidence in his or her malignant diagnosis. In this study, encompassing 15 years of practice, the outcome of fine needle aspirates of the pancreas diagnosed as atypical were retrospectively reviewed.
Design: A computerized search of the cytology laboratory information system from July 22, 1993 through July 21, 2008 was performed and all pancreatic FNA cases diagnosed as atypical were identified. All correlating cytology and surgical pathology reports from these cases were reviewed as were selective cytology and surgical pathology slides.
Results: During this 15-year period, indeterminant cytologic diagnoses of atypical cells were rendered in 127 pancreatic FNA cases for which confirmatory follow-up material was available. There were 74 males and 53 females ranging in age from 34 to 86 (mean age: 63). In 54 cases (43%), the diagnosis of malignancy was confirmed by follow-up surgical pathology (Whipple resection-31 cases, surgical biopsy-3 cases) or cytology (repeat FNA-13 cases, brush cytology-3 cases). In 25 cases (20%), a suspected diagnosis of malignancy was confirmed by the documentation of metastatic disease by surgical pathology (23 cases) or FNA (3 cases) at the metastatic sites. In total, 79 of 127 atypical pancreatic FNA cases were confirmed as adenocarcinoma (62%). In 17 cases (13%), a histologic diagnosis of intraductal papillary mucinous neoplasia neoplasm (IPMN) was rendered. Other malignancies noted on follow-up included 4 cases of pancreatic endocrine neoplasia, 3 cases of metastatic carcinoma and 1 case of gastric lymphoma. A total of 22 benign cases were present among the 127 atypical FNA cases. These included 16 cases of chronic pancreatitis, 2 cases of serous cystadenoma and 4 other benign lesions.
Conclusions: The majority of pancreatic FNA cases diagnosed as atypical were proven to be adenocarcinomas (62%), other malignancies (6%) or IPMNs (13%). The high yield of malignancy following a pancreatic FNA diagnosis of atypical cells reflects the natural diagnostic conservatism of most cytopathologists. Because chronic pancreatitis and other benign lesions were included among the group of cases diagnosed as atypical by pancreatic FNA, abandonment of this category is not warranted. Careful re-examination of atypical pancreatic FNAs that prove to be malignant could enhance the cytopathologists' diagnostic skills.
Category: Gastrointestinal

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 115, Tuesday Afternoon