What is the diagnosis and treatment of Intraductal Papillary Mucinous Neoplasm (IPMN)?

From the Guidelines

Patients with IPMNs >40 mm should be considered for surgical resection due to the increased risk of harbouring malignancy. The management of intraductal papillary mucinous neoplasms (IPMNs) depends on various risk factors, including the size of the cyst, with larger cysts being more likely to harbor malignancy 1. According to the european evidence-based guidelines on pancreatic cystic neoplasms, patients with IPMNs >40 mm have an increased risk of malignancy, ranging from 12% to 47% in cases of a cyst ≥30 mm 1.

Key Considerations

• Cyst size alone is not an appropriate indication for surgery, as the risk of malignancy is actual but low 1
• The presence of multiple risk factors increases the sensitivity to detect malignancy 1
• MRI/MRCP is the preferred method for follow-up of pancreatic cystic neoplasms, including IPMNs, due to its high sensitivity and accuracy 1
• Patients with IPMNs may require lifelong imaging follow-up, and MRI/MRCP is a safer option compared to CT scans, which carry a risk of malignancy due to repeated exposure to ionising radiation 1

Surveillance and Monitoring

• For smaller lesions (<2cm) without concerning features, MRI/MRCP is recommended every 6-12 months 1
• Larger lesions or those with worrisome characteristics require more frequent imaging or endoscopic ultrasound
• High-risk features warranting surgical consultation include main pancreatic duct involvement, duct dilation >5mm, solid components, jaundice, or cyst size >3cm 1

From the Research

Definition and Characteristics of IPMN

• Intraductal papillary mucinous neoplasms (IPMNs) are neoplasms characterized by ductal dilation, intraductal papillary growth, and thick mucus secretion 2
• IPMNs can be classified into main duct IPMN, branch duct IPMN, and mixed-type IPMN 3, 2

Diagnosis and Management of IPMN

• Magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) are primary investigations in diagnosing and following up on IPMN patients 2
• The role of pancreatoscopy and the analysis of aspirated cystic fluid for cytology and DNA analysis is still to be established 2
• Resection is recommended for most main duct IPMNs, mixed variants, and symptomatic branch duct IPMNs 3, 2

Indications for Resection

• Indications for resection in patients with IPMN include cancer, cancer prevention in patients at high risk for malignant transformation, and management of symptoms 3
• Size alone should not be the determining oncologic factor for resection, although size or anticipated growth may complicate the ability to safely extirpate the lesion 3
• Other factors that should be considered in determining whether to resect include number of lesions, need for prolonged surveillance, inability to adequately perform noninvasive surveillance, and patient tolerance of risk 3

Surveillance and Follow-up

• The optimal surveillance regimen depends on the timing and incidence of "recurrence" and "new metachronous IPMN development" 3
• Patients should be followed at least annually with history and physical and optimal cross-sectional imaging 3
• Endoscopy and cytopathologic assessment should be considered at least biannually and more often when indicated by patient symptoms or concerning radiographic features 3
• The surveillance interval should be decreased and extent of testing increased based on patients with higher oncologic risk stratification 3

Recent Guidelines and Recommendations

• The 2024 international evidence-based Kyoto guidelines for the management of IPMN of the pancreas propose a new management algorithm and include imaging findings from endoscopic ultrasound (EUS) and the results of cytological analysis from EUS-guided fine needle aspiration technique in the assessment of high-risk stigmata (HRS) and worrisome features (WF) 4
• The guidelines also recommend two options, "stop surveillance" or "continue surveillance for possible development of concomitant pancreatic ductal adenocarcinoma", for small unchanged branch duct IPMNs after 5 years surveillance 4
• The Society of Abdominal Radiology (SAR) recommends standardized imaging and reporting for IPMN, including how to measure IPMN, define reporting terminology, standardize reporting, and unify guidelines for surveillance 5