Abstract
Gastrointestinal tract duplication cysts are rare congenital gastrointestinal malformation in young patients and adults. They consist of foregut duplication cysts, small bowel duplication cysts, and large bowel duplication cysts. Endoscopic ultrasound (EUS) has been widely used as a modality for the evaluation and diagnosis of duplication cysts. EUS is the diagnostic tool of choice to investigate duplication cysts since it can distinguish between solid and cystic lesions. The question of whether or not to perform EUS-fine needle aspiration (EUS-FNA) on a lesion suspected of being a duplication cyst is controversial as these lesions can become infected with significant consequences, although EUS-FNA is often required to obtain a definitive diagnosis and to rule out more ominous lesions. This manuscript will review the literature on duplication cysts throughout the body and will also focus on the role of EUS and FNA with regards to these lesions.