[401] Characterization of the Atypical Diagnostic Category in Endoscopic Ultrasound-Guided Fine Needle Aspiration (EUS-FNA) of the Pancreas: A Ten Year Experience

Mark Moore, Jimmie Stewart III, Kasturi Das. University of Wisconsin School of Medicine and Public Health, Madison, WI

Background: Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is a critical diagnostic and staging tool for solid and cystic lesions of the pancreas. Few studies have characterized the spectrum of lesions that fall into the atypical category and compared this result to concurrent core needle biopsy (CNB) and subsequent resection. We believe this is one of the first large studies of this kind.
Design: Data were collected retrospectively on all patients undergoing EUS-FNA at our institution from April 2002 to July 2012. Cases diagnosed by cytology as atypical were selected. The results of CNB and surgical resection specimens were obtained when available. Clinical data were collected from patient charts.
Results: A total of 1,106 EUS-FNA cases were identified from 2002 to 2012, of which 50 cases (4.5%) were categorized as atypical. Of the atypical cases, cystic lesions accounted for 44% of lesions, solid 20%, solid & cystic 28% and no definitive mass was identified in 8% of cases. The outcome of the 50 atypical cases was as follows: 5 went to CNB (10%), 8 underwent resection (16%), 26 had clinical diagnoses (54%) and 11 had no follow-up (22%). The diagnoses are provided in Table1. A definitive diagnosis was obtained in all five of five (100%) CNB obtained. The FNA under-diagnosis in all of the 8 resected cases was attributable to low cellularity. Of the 39 atypical cases with a diagnosis rendered, 11 cases (28%) were malignant, the remaining 28 (72%) were benign cysts or non-neoplastic processes.

Conclusions: In EUS-FNA of the pancreas, the atypical category is more frequently applied to cystic lesions than to solid pancreatic masses. Low cellularity is the most common reason for applying this category, which may be related to operator-dependent sampling issues or the anatomic nature of the lesion. Concurrent CNB is an effective diagnostic adjunct to FNA when possible. Clinicopathologic correlation is essential for optimal management.
Category: Cytopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 66, Monday Afternoon


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