Diagnosis of cystic neoplasms with endoscopic ultrasound.
From the data that are currently available, it appears that EUS can help to reliably distinguish between the majority of benign and neoplastic cystic lesions. In equivocal cases, or cases where a high suspicion for malignancy exists, the use of EUS-guided FNA for obtaining cytology and cystic fluid for analysis of various tumor markers, gives the best diagnostic yield. Occasionally, despite a complete evaluation of a cystic mass, the cyst type may not be determined. The decision regarding further management of these lesions should be based on a combination of factors including symptoms, cyst size, EUS morphology and the patient's overall medical condition. In the case of symptomatic, large, or suspicious lesions where the patient is a good surgical candidate, surgical resection should be performed. However, it becomes more difficult in the case of asymptomatic, small cystic lesions where the patient is not an optimal surgical candidate. In the latter scenario, applying EUS criteria for follow-up of small pancreatic cystic lesions as reported by Ikeda et al can help in the decision-making process. In this study, Ikeda et al reported on 31 patients with pancreatic cystic lesions of unknown etiology that were followed-up with semi-annual EUS exams over a 3-year period. In 87.1% of these lesions, the size was less than 2 cm. Their criteria included 1) a clear thin wall, 2) smooth contour, 3) round or oval shape, 4) no septum or nodules, 5) asymptomatic clinical presentation, and 6) no findings of chronic pancreatitis. The cystic lesions remained stable in 30/31 patients, and only one lesion increased in size. This lesion was resected and was found to be a retention cyst. We are optimistic that the role of EUS in the management of cystic neoplasms will continue to evolve and expand as future studies evaluate the clinical utility of imaging modalities for the optimal practice algorithm for managing these neoplasms.