EUS Elastography for the Characterization of Solid Pancreatic Masses

Background: Differential diagnosis of solid pancreatic masses remains a challenge. EUS elastography, by analyzing tissue stiffness of the mass, may be of help in this setting.

Objective: To evaluate the different elastographic patterns of solid pancreatic masses and the diagnostic accuracy of EUS elastography for malignancy.

Design: Prospective, consecutive, descriptive study with a second blind evaluation of elastographic patterns for concordance analysis and use of a well-defined reference method for calculation of diagnostic accuracy.

Patients: This study involved 130 consecutive patients with solid pancreatic masses and 20 controls with normal pancreases.

Intervention: EUS elastography was performed by using a linear Pentax echoendoscope and Hitachi EUB-8500 US.

Main Outcome Measurements: Elastographic patterns of solid pancreatic masses and accuracy of the technique for malignancy.

Results: Mean (SD) size of the masses was 30.9 (12.5) mm. The final diagnosis was malignant tumor in 78 patients, inflammatory mass in 42 patients, and neuroendocrine tumor in 10 patients. Four elastographic patterns were described, with a high concordance among 2 blinded investigators. A green-predominant pattern, either homogeneous or heterogeneous, excluded malignancy with a high accuracy. On the contrary, a blue-predominant pattern, either homogeneous or heterogeneous, supported the diagnosis of malignant tumor. Sensitivity, specificity, positive and negative predictive values, and overall accuracy of EUS elastography for diagnosis of malignancy were 100%, 85.5%, 90.7%, 100%, and 94.0%, respectively.

Limitation: Single-center study.

Conclusion: EUS elastography is a useful tool for differential diagnosis of solid pancreatic masses. It provides specific patterns supporting the benign or malignant nature of the disease.