Abstract

Background
/Aims: A macrocystic variant of a serous cystadenoma (M-SCA) is usually indistinguishable from a mucinous cystadenoma (MCA) as a result of their morphologic similarity on conventional imaging studies. However, a MCA requires a resection due to its malignant potential. The aim of this study was to determine the EUS morphological characteristics of a M-SCA to determine if they could be used to help differentiate it from MCA. Methods: The clinical and EUS morphologic characteristics were examined in 31 consecutive patients with M-SCA and MCA who underwent surgery. Results: Resected specimens were available from 11 M-SCAs and 20 MCAs. Significant differences were observed with regard to the age and location within the pancreas. On EUS, most of the M-SCA contained microcysts (82%) compared with only 15% of MCA cases, and a lobulated configuration of the cyst was observed more frequently in the M-SCA cases than in the MCA (91% vs. 25%). The combination of microcysts and the lobulated configuration of the cysts had a 100% specificity and positive predictive value for differentiating M-SCA from MCA. Conclusions: M-SCA tends to occur at a relatively younger age than MCA, and is located mainly in the head of the pancreas. Although there is considerable morphological similarity between M-SCA and MCA on the conventional imaging modalities, the morphological characteristics obtained from EUS including microcysts with a lobulated configuration may help to make a distinction between M-SCA and MCA. (Korean J Gastrointest Endosc 2006;32:109⁣115)

• Keywords: Serous cystadenoma, Mucinous cystadenoma, Pancreas, EUS