The characteristics and outcome of intraductal papillary mucinous neoplasm of the pancreas: an observational study.

Background: Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic cystic lesions with variable risk for malignant transformation. This observational study assessed the long-term natural history of IPMNs, focusing on risk stratification based on imaging and histological features.

Methods: We retrospectively reviewed 93 patients with IPMN confirmed by MRI and endoscopic ultrasound (EUS) or both. All patients had a minimum follow-up of 5 years. Demographic, clinical, imaging, procedural, and outcome data were collected. IPMN characteristics including cyst size, duct size, duct involvement, and location were evaluated at baseline. The primary outcome was progression to high-grade dysplasia or invasive carcinoma. Secondary outcomes included the need for surgery, cyst progression, and IPMN-related mortality.

Results: The cohort included 93 patients (65.6% female, mean age 70.9 ± 9.9 years). The majority (92.5%) had branch duct IPMN. The mean cyst size was 1.53 ± 1.57 cm, and the duct size was 2.69 ± 1.79 mm. High-grade dysplasia was found in 9.7%. Surgical resection was significantly associated with cyst size >2.6 cm (P = 0.031), duct dilation >5.3 mm (P = 0.004), and main/mixed duct involvement (P < 0.001). Additionally, cyst wall thickening (60%) and mural nodule (67%) were significantly associated with surgical resection. One patient progressed to invasive carcinoma. No IPMN-related deaths were reported.

Conclusions: IPMNs evaluated and monitored with MRI/EUS demonstrate indolent behavior over extended follow-up. Surgical resection should be considered based on duct type, cyst size, and presence of dysplasia. Long-term surveillance remains essential for appropriate risk stratification.