Role of Endoscopic Ultrasonography in Follow-Up of Branch Duct Type Intraductal Papillary-Mucinous Neoplasms of the Pancreas

Background/Aim: The aim of this study was to elucidate the role of endoscopic ultrasonography (EUS) in follow-up of the patients with branch duct type intraductal papillary-mucinous neoplasms of the pancreas (IPMNs). Methods: Sixty-five patients (forty-seven men and eighteen women) with branch duct type IPMNs were selected for follow-up and examined by EUS two or more times (mean, 3 times). Patients who had apparent mural nodules were excluded from follow-up study. All patients underwent initial endoscopic retrograde pancreatography (ERP), magnetic retrograde cholangiopancreatography (MRCP), and computed tomography (CT). Serial changes of the maximum cystic diameter and the presence of mural nodule were studied during the observation periods ranged from 19 to 172 months (mean, 87 months). Results: Six (9%) of 65 patients exhibited obvious progression of cystic dilatation. New apparent mural nodules were detected in 6 cases (9%) during the observation periods. These obvious changes were observed after a 19 to 114 months follow-up period (mean, 80 months). Of six patients with mural nodules, four cases underwent surgery after follow-up study, and the pathologic diagnosis was adenoma in two and non-invasive carcinoma in two. Mural nodules were accurately diagnosed in 6 cases (100%) by EUS, whereas in one (17%) by CT and in 0 (0%) by MRCP. Six patients with cystic size enlargement were followed up without surgical resection. None of the remaining 53 patients (82%) showed increases in cystic diameter and new apparent mural nodules. Conclusions: Mural nodule is an important factor affecting the follow-up, and most of branch duct type IPMNs without apparent mural nodules remained unchanged. EUS is the most sensitive method to detect mural nodules in follow-up of branch duct type IPMNs.