[1726] Slide Based Molecular Analysis Technique for the Work-Up of Indeterminate Atypical Pancreatic Lesions

KD Denning, TC Pereira, SD Finkelstein, YL Liu, MK Dhawan, A Kulkarni, JF Silverman. Allegheny General Hospital, Pittsburgh; RedPath Integrated Pathology Inc., Pittsburgh; Allegheny Center for Digestive Health, Pittsburgh

Background: Fine needle aspiration cytology (FNAC) is often the initial step in the diagnosis of solid and cystic lesions of the pancreas. Occasionally, the diagnosis can be challenging when benign ductal cells show inflammatory atypia and reparative changes in the setting of pancreatitis making it difficult to separate these lesions from well differentiated adenocarcinoma (AC). Recent studies have shown that pancreatic ACs show allelic imbalance damage for a subset of mutational markers. In this study we evaluated surgical and clinical outcomes of patients with atypical FNAC to determine if molecular analysis using a slide based technique can provide additional information for a more definitive diagnosis.
Design: Slide based microdissection followed by PCR studies were performed on 26 indeterminate atypical FNA specimens of solid and cystic pancreatic lesions. Molecular studies were performed following microdissection of multiple clusters of representative atypical cells from an original FNAC slide. The FNAC and molecular diagnosis (MD) was determined to be benign (non-aggressive) or dysplastic/malignant (aggressive) for each patient based on cytology criteria and the number of molecular abnormalities. The clinical or surgical follow-up (FU) was compared to the FNAC and MD.
Results: Of the 26 patients, 3 patients lacked surgical and/or clinical FU information. Fourteen (60.9%) patients had FNAC and MD that predicted the correct FU diagnosis of a benign course. In 4 (17.2%) patients FNAC was benign, but the MD indicated a dysplastic or malignant process and the FU revealed a malignancy. In 2 (8.7%) patients, the FNAC and MD suggested a dysplastic or malignant diagnosis and the patients were found to have AC. Two (8.7%) patients had a benign FNAC and MD, but the patients were found to have AC. One (4.3%) patient had a dysplastic FNAC diagnosis, but the MD supported a benign diagnosis and the patient was found not to have cancer on FU.
Conclusions: Our results show that using the techniques of PCR molecular analysis of microdissected material from slides was helpful in the work-up of indeterminate, atypical pancreatic FNAs. In approximately 74% of the cases, FNAC with a slide based molecular analysis predicted the correct outcome which could be of value in making a more specific diagnosis and thereby help in the appropriate management of the patient.
Category: Techniques

Monday, March 9, 2009 9:30 AM

Poster Session I Stowell-Orbison/Autopsy Award # 244, Monday Morning