[377] Diagnostic Error Assessment of EUS-FNA of Neuroendocrine Neoplasms of the Pancreas

Kari K Hooper, Shaoying Li, Faisal Mukhtar, Isam-Eldin Eltoum. University of Alabama at Birmingham, Birmingham, AL

Background: Standardization of error classification in anatomic pathology has become an important issue due to the difficulty in accurate meta-analysis of error rates and causes. Zarbo et al (Arch Pathol Lab Med – Vol 129, Oct 2005) have proposed taxonomy and measurement tools to obviate previous inconsistency in error reporting. The objective of this study is to assess the extent of error occurring in cytopathologic diagnosis of neuroendocrine lesions of the pancreas, classify these errors and determine their impact on clinical outcomes.
Design: We collected information on all cases diagnosed as neuroendocrine neoplasm either by EUS-FNA in cytology or by surgical pathology from 2000-2012. Utilizing the standardized error and harm classification noted above, we reviewed the cytology and surgical pathology material and evaluated the type and the cause of diagnostic errors and their impact on the patient.
Results: During the study period, 177 patients who had EUS-FNA were diagnosed with a neuroendocrine neoplasm either by cytology or by surgical pathology (age range 15-90 yrs, 91 males). 80 of these cases had surgical follow up at our institution with surgical specimens available for review. Of these 80 cases, 56 had an adequate cell block from the EUS-FNA and immunohistochemistry was performed. There were 13 discrepancies between cytologic and surgical pathologic diagnoses (16% of EUS-FNA cases with surgical follow up). There were no false positive cases, 9 false negative cases (69% of total errors, 14% of cases with follow up) and 4 misclassifications (31% of total errors, 5% of cases with follow up). The false negative cases consisted of 3 interpretation errors and 6 cytology sampling errors. The misclassifications consisted of 3 cases of solid pseudopapillary neoplasm diagnosed as neuroendocrine neoplasm on cytology and one case of neuroendocrine carcinoma diagnosed as adenocarcinoma on cytology. There were no surgical pathology errors. All errors were associated with no or minimal harm, as the false negative cases received surgical intervention due to high clinical or radiologic suspicion. There was no moderate or major harm.
Conclusions: This study demonstrates error rates and misclassification associated with neuroendocrine neoplasms of the pancreas. EUS-FNA of pancreatic neuroendocrine neoplasms has an excellent positive predictive value, with no false positive diagnoses made in this 12-year study. When an adequate sample is obtained, the most significant error is misclassification, most often associated with solid pseudopapillary neoplasm. The impact of these errors is minimal.
Category: Cytopathology

Tuesday, March 5, 2013 1:00 PM

Poster Session IV # 77, Tuesday Afternoon


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