What are the guidelines for diagnosis and follow-up of Intraductal Papillary Mucinous Neoplasms (IPMNs)?

From the Guidelines

The diagnosis and follow-up of Intraductal Papillary Mucinous Neoplasms (IPMNs) should prioritize pancreatic MRI as the preferred method for surveillance, considering its accuracy, cost, and modality-related risk factors, as recommended by the European evidence-based guidelines on pancreatic cystic neoplasms 1.

Key Considerations for Diagnosis and Follow-up

• IPMNs should be initially evaluated with high-quality cross-sectional imaging, preferably magnetic resonance cholangiopancreatography (MRCP) or pancreatic protocol CT scan.
• For diagnosis, clinicians should assess for high-risk features including main pancreatic duct involvement (main-duct or mixed-type IPMN), main duct dilation ≥10 mm, presence of an enhancing solid component, or obstructive jaundice with a pancreatic head lesion.
• Branch-duct IPMNs without high-risk features can be monitored, while those with concerning features warrant surgical evaluation.
• The follow-up schedule depends on cyst size, with lesions <1 cm imaged every 2-3 years, those 1-2 cm annually for the first 2-3 years then less frequently if stable, and those 2-3 cm every 6-12 months initially.
• Endoscopic ultrasound with fine needle aspiration (EUS-FNA) should be considered for cysts with worrisome features or when diagnosis is uncertain.
• Cyst fluid analysis for CEA levels and cytology can help differentiate mucinous from non-mucinous lesions.

Importance of Individualized Management

• IPMNs represent a spectrum from benign to malignant lesions with varying progression rates, necessitating individualized management based on patient factors including age, comorbidities, and surgical risk.
• Lifelong surveillance is recommended following resection of an IPMN, with follow-up imaging using MRI or EUS, as recommended by the European evidence-based guidelines on pancreatic cystic neoplasms 1.
• The risk of malignant transformation and the morbidity of pancreatic surgery should be balanced in the management of IPMNs, with consideration of the latest research accomplishments and new avenues for translational research 1.

Recent Guidelines and Recommendations

• The American College of Radiology (ACR) Appropriateness Criteria recommend CT or MRI for follow-up of pancreatic cysts, with consideration of the risk of malignant transformation and the morbidity of pancreatic surgery 1.
• The Verona Consensus Meeting recommends a systematic approach to the pathologic evaluation and reporting of IPMNs, including the documentation of tumor size, invasive component, and main duct diameter 1.

From the Research

Diagnosis of Intraductal Papillary Mucinous Neoplasms (IPMNs)

• IPMNs are characterized by ductal dilation, intraductal papillary growth, and thick mucus secretion 2
• Magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS) are primary investigations in diagnosing and following up on these patients 2
• EUS-guided fine-needle aspiration cytology diagnosis of IPMN is highly predictive of pancreatic neoplasia 3
• The role of EUS in the management of IPMNs includes assessing the morphology of cysts, identifying high-risk characteristics, and allowing aspiration of cyst fluid for analysis 4

Follow-up of IPMNs

• Periodic imaging follow-up is useful to detect a malignant IPMN 5
• Changes in main pancreatic duct (MPD) diameter, cyst diameter, and/or size of the protruding lesion are practical criteria for selecting surgery 5
• Follow-up management is important to monitor growth and recurrence, and risks from repeated radiation exposure should be taken into account 6
• The follow-up of these patients could vary from 6 months to 1 year and would depend on the risk stratification for invasive malignancy and the pathology of the resected specimen 2

Risk Stratification and Management

• The reported incidence of malignancy varies from 57% to 92% in the main duct-IPMN (MD-IPMN) and from 6% to 46% in the branch duct-IPMN (BD-IPMN) 2
• Features of high-risk malignant lesions include obstructive jaundice, mass lesion of >30 mm, enhanced solid component, and MPD of size ≥10 mm 2
• Resection is recommended for most MD-IPMN, mixed variant, and symptomatic BD-IPMN 2
• Current guidelines suggest that MD-IPMNs should generally be considered for resection without further evaluation 4