Context: Recent studies have shown high amplitude K-ras gene mutation and allelic imbalances are predictive of malignancy in pancreatic cysts.
Objective: Our purpose is to determine the added benefit of molecular testing in diagnosing small pancreatic cysts.
Design: Retrospective, single-institution study.
Patients: Patients with pancreatic cysts (less than, or equal to, 3 cm) who presented for EUS evaluation.
Intervention: EUS-guided pancreatic cyst aspiration cytology, carcinoembryonic antigen (CEA) level determination, and detailed DNA analysis including K-ras gene mutation and allelic imbalance.
Main outcome measurements: Ability of cyst fluid DNA analysis to render a diagnosis compared with cytology and CEA level determination.
Results: Diagnostic agreement was seen in 55.6% (35/63) of cases. In 10 cases (15.9%), there was disagreement between cytology and molecular. Molecular testing provided a diagnosis in 20 cases (31.7%) when either cytology was unsatisfactory, or CEA not elevated (less than 192 ng/mL). Elevated CEA levels were seen in 16 cases (25.4%), each diagnosed as a mucinous lesion with molecular analysis.
Conclusions: Molecular analysis of pancreatic cyst fluid adds diagnostic value in scant specimens when cytology may be unsatisfactory and CEA unreliable.