Evaluation of MRCP Findings in Distinguishing Benign from Malignant Causes of Isolated Main Pancreatic Duct Dilation.

PURPOSE: This study aimed to investigate morphological features on magnetic resonance cholangiopancreatography (MRCP) that may help distinguish benign from malignant causes of isolated main pancreatic duct (MPD) dilation detected without a visible mass or obstructive pathology, and to propose a management strategy applicable in clinical practice.

MATERIALS AND

METHODS

Ninety-two patients with isolated MPD dilation detected on MRCP at our institution between November 2015 and March 2025 were retrospectively evaluated. The following MRCP parameters were assessed: maximum pancreatic duct diameter, location of dilation, dilation pattern, presence of duct stricture and stricture segment length with termination pattern if present, parenchymal atrophy, pancreatic duct anomalies, common bile duct-pancreatic duct junction configurations, and presence of branch duct dilation or cysts.

RESULTS

Cases were classified as benign in 85.9% (n=79) and malignant in 14.1% (n=13). Stricture segment length was significantly greater in the malignant group, with a median of 7.0 mm (Q1-Q3: 5.0-12.0) compared to 3.7 mm (Q1-Q3: 2.5-7.0) in the benign group. Although branch duct dilation/cyst size was larger in the malignant group (median: 9.6 mm vs. 6.8 mm), this difference was not statistically significant (p > 0.05). Regarding dilation location, the segment with maximum dilation was predominantly at the pancreatic neck in malignant cases (53.8%), whereas the pancreatic head was predominant in benign cases (88.6%). Stricture termination patterns differed significantly between groups: abrupt termination predominated in malignant cases (88.9%), while tapering termination was more frequent in the benign group (72.7%).

CONCLUSION

MRCP is a valuable non-invasive tool for the further characterization of isolated MPD dilation. Findings such as increased stricture segment length (≥7 mm), dilation localized to the pancreatic neck, and abrupt stricture termination may help distinguish malignant from benign causes. These morphological features may support clinical decision-making when determining the need for further invasive investigations.

KEY POINTS: · Stricture segment length ≥7 mm and abrupt duct termination are significant morphological features suggestive of malignancy in isolated MPD dilation.. · Maximum dilation localized to the pancreatic neck may raise suspicion for an underlying malignancy, though further validation is required.. · MRCP serves as a valuable adjunct in the diagnostic work-up of pancreatic duct changes, potentially helping to identify cases that require invasive investigations such as Endoscopic ultrasound (EUS) or surgical consultation.. · Serum biomarkers (CA 19-9, CEA) showed no significant difference between benign and malignant groups, highlighting the importance of morphological evaluation..

CITATION FORMAT: · Çınar E, Uysal FT, Gürbüz AF et al. Evaluation of MRCP Findings in Distinguishing Benign from Malignant Causes of Isolated Main Pancreatic Duct Dilation. Rofo 2026; DOI 10.1055/a-2863-2316.