Diagnosis of an aneurysm masquerading as a pancreatic-cyst lesion at EUS

BackgroundEUS-guided FNA is commonly performed for evaluating pancreatic-cyst lesions. However, not all such lesions are true cystic neoplasms of the pancreas.ObjectiveDetermine the frequency at which aneurysms mimicking cysts are encountered during EUS evaluation of the pancreas.Study DesignObservational study.SettingTertiary referral center.PatientsConsecutive patients found to have pancreatic cyst lesions at EUS.InterventionsPatients with a cyst lesion in the pancreas that was suspicious for an aneurysm at EUS underwent abdominal CT imaging for a definitive diagnosis.Main Outcome MeasuresTo determine the frequency at which aneurysms are encountered during EUS while evaluating pancreatic-cyst lesions and to describe the EUS characteristics of an underlying aneurysm.ResultsFour of 413 lesions (0.97%, 95% confidence interval 0.26%-2.5%) that appeared as pancreatic cysts at EUS were diagnosed to be aneurysms: 2 were splenic artery aneurysms, 1 was an aneurysm of the gastroduodenal artery, and another was an infrarenal aortic aneurysm. The aneurysms had a characteristic donut-like appearance at EUS: a thick outer wall with a central anechoic area.LimitationsObservational study; small sample size.ConclusionsAneurysms can masquerade as pancreatic-cystic lesions. Awareness of this entity is important because an inadvertent FNA during EUS may potentially lead to serious complications.