Cyst wall puncture and aspiration during EUS-guided fine needle aspiration may increase the diagnostic yield of mucinous cysts of the pancreas.

Background: Pancreatic cysts are common, however, their diagnosis and classification remains a challenge despite advances in cross-sectional imaging and endoscopic ultrasound with fine needle aspiration (EUS-FNA).
Objective: To determine the incremental yield of cytologic examination of material obtained from targeted fine needle aspiration ("puncture") of the cyst wall after aspiration of fluid for CEA.
Design: Retrospective consecutive series.
Patients and Setting: Consecutive patients undergoing EUS-FNA of a pancreatic cyst by 2 expert endoscopists at a single tertiary care center between January 2006 and June 2008.
Intervention: Standard EUS-FNA of pancreatic cysts was carried out, and after cyst fluid aspiration the cyst wall was punctured and aspirated (CWP) to obtain epithelium for cytologic analysis.
Main Outcome Measurements: The diagnostic yields of carcinoembryonic antigen (CEA) obtained from cyst fluid and of cytology obtained from CWP. CEA greater than192 ng/mL was considered diagnostic of a mucinous cyst.
Results: One hundred seven patients underwent EUS-FNA with CWP. Sixteen (31%) of 52 patients with CEA <192 ng/mL had cytology positive for mucinous epithelium, whereas 15 (47%) of 32 cysts with an insufficient amount of fluid for CEA analysis had positive cytology from CWP. The additional, cumulative diagnostic yield for mucinous cysts was therefore, 37%. Of 55 cysts diagnosed as mucinous, more (56%) were diagnosed by CWP cytology alone than by CEA (P<0.05).
Limitations: Retrospective design and limited surgical pathology.
Conclusions: Cyst wall puncture and aspiration during routine EUS-FNA may be a safe, easily applied, and inexpensive technique for improving the diagnostic yield for mucinous cysts of the pancreas.