EUS-guided FNA with cyst fluid analysis in pancreatic cystic lesions

Objectives: Up to 10% of pancreatic cysts are cystic neoplasms, with 40% initially misdiagnosed as pseudocysts. Malignant cystic neoplasms are often surgically resectable. Non-malignant mucinous cysts are premalignant and thus resection is recommended. We investigated the utility of EUS and EUS-guided fluid aspiration for the differentiation of these lesions. Methods: Between 10/95 and 9/97, 45 pts underwent 49 EUS-FNA's. Fluid was sent for cytology, mucin staining and tumor markers (CEA, CA-125, CA 19-9, CA 72-4, TPA, CA15-3). Morphology was retrospectively classified per recently published criteria. Definitive diagnosis is available in 20 pts. Results: Complications consisted of self-limited pancreatitis in 2 of 49 aspirations (4%). There were 12 adenocarcinomas, 3 mucinous cystadenomas, 3 pseudocysts, 1 serous cystadenoma and 1 retention cyst. The first 15 were considered mucinous; the latter 5 were considered benign, non-mucinous. Detection of Malignancy Test Sens Spec Ace PPV NPV Cytology 57%, 100% 80% 100% 73% CA 125 (>60) 67% 88% 76% 86% 70% TPA (> 100,000) 43% 100% 73% 100% 67% CA 19-9 (>50.000) 30% 50% 39% 43% 36% CA 72-4 (>150) 20% 100% 53% 100% 47% CA 15.3 (>30) 40% 100% 67% 100% 57% Malignancy Panel (Cytol or marker except CA 19-9) 83% 88% 86% 83% 88% Identification of Mucinous Lesions Test Sens Spec Ace PPV NPV Cytology or Mucin Stain + 75% 80% 77% 86% 67% CEA (>50) 92% 80% 88% 92% 80% Morphology 40% 100% 55% 100% 36% Mucin Panel 100% 60% 86% 80% 100% Conclusions: EUS morphology cannot accurately identify mucinous pancreatic neoplasms, however this can be reliably and safely accomplished with EUS-guided fluid analysis. These cysts can then be further characterized as malignant or benign by the combination of cytology and a panel of tumor markers.