Diagnostic yield of endoscopic ultrasonography (EUS), EUS-guided fine-needle aspiration (EUS-FNA), cyst fluid tumour markers & cytology in pancreatic cystic neoplasms

Background: Cystic neoplasms of the pancreas represent a heterogeneous group of tumours with varied malignant potential. Aim of this prospective study was to evaluate EUS, EUS-FNA and cyst fluid analysis in distinguishing serous cystadenomas (SC) and mucinous cystic neoplasms (MCN). Methods: 4 patients with microcystic and 9 macrocystic SC (4 men, 9 women, mean age 55), 15 MCN (3 men, 12 women, mean age 55) and 10 pancreatic pseudocysts as controls (1 man, 9 women, mean age 43) were investigated by EUS (Olympus GF UCT140; Aloka ProSound 5000) from I/2003 to II/2006. Cyst fluid evaluation was done for cytology, amylase, CEA, CA 19–9, CA 72–4 and CA 15–3 (RIA). The final diagnosis was based on surgery & histology (14 patients) and/or follow-up after EUS-FNA (mean 15 months). In the MCN-group 12 mucinous cystadenomas, 2 cystadenocarcinomas and 1 malignant IPMT were found. Results: Cytology (including staining for mucin) was diagnostic in 2/13 SC (15%), 10/15 MC (67%) and negative in all controls. Fluid CEA in MCN (median 78, 95%CI 0–25514) was significantly higher compared both with SC (median 1, 95%CI 0–748, p=0.005) and controls (median 2.5, 95%CI 0–7.8, p=0.001). Total 9/13 SC (69%), 10/10 controls (100%) were below and 11/15 MCN (73%) were above 16µg/L cut-off value for fluid CEA. Differences of other tumour markers were not significant. Accuracy of EUS-FNA with final diagnosis was 91%. Conclusions: EUS-FNA with cyst fluid CEA and cytology are useful tools in differentiating SC, MCN and pseudocysts of the pancreas.