2. Pancreatic Cystic Lesions

 

 

Overview

  • Prevalence: PCN are found in 2–45% of the general population, often incidentally.

  • Clinical Importance: Spectrum ranges from benign to malignant, emphasizing accurate diagnosis and timely intervention to prevent pancreatic cancer.

Classification of PCN

Types of PCN

Type

Key Features

Malignancy Risk

Intraductal Papillary Mucinous Neoplasms (IPMN)

Mucin-producing. Communication with pancreatic duct.

Varies; high for main duct type.

Mucinous Cystic Neoplasms (MCN)

No ductal communication; ovarian stroma in histology.

Intermediate.

Serous Cystic Neoplasms (SCN)

Honeycomb appearance. Glycogen-rich epithelium.

Rarely malignant.

Solid Pseudopapillary Neoplasms (SPN)

Solid and cystic components. Young women predominant.

Rare but potentially aggressive.

Pseudocysts

Non-neoplastic; fluid-filled collections secondary to pancreatitis.

Benign.

Pathophysiology

Biomarkers in PCN Diagnosis

Biomarker

Use

Sensitivity/Specificity

CEA (≥192 ng/mL)

Differentiates mucinous from non-mucinous cysts.

Sensitivity: 63–91%; Specificity: Moderate.

GNAS/KRAS mutations

Indicative of mucinous cysts (e.g., IPMN, MCN).

High specificity.

Amylase (<250 U/L)

Excludes pseudocysts when low.

Specificity: 98%.

CA 19-9

Suggests malignancy in IPMN.

Low specificity as standalone.

Imaging Features

Modality

Use

Advantages

MRI/MRCP

Detects ductal communication, septations.

High sensitivity for soft tissue.

CT

Defines calcifications, staging malignancy.

Excellent for structural details.

Endoscopic Ultrasound (EUS)

Evaluates mural nodules and vascularity.

Complements CT and MRI findings.

EUS-FNA

Allows fluid sampling for biomarker analysis.

Accurate for mucinous vs non-mucinous cysts.

Diagnostic Criteria and Risk Stratification

Indications for Surgical Referral

Feature

Risk

Management

MPD ≥10 mm

High

Surgical resection recommended.

Enhancing mural nodule ≥5 mm

High

Surgical resection.

Obstructive jaundice

High

Surgical exploration necessary.

MPD 5–9.9 mm

Intermediate

Close monitoring or resection.

Rapid cyst growth (≥5 mm/year)

Intermediate

Enhanced imaging surveillance or surgery.

Management Flowchart for IPMN

  1. Initial Assessment:

    • Imaging with MRI/MRCP and/or CT.

    • Assess symptoms, ductal involvement, and size of cysts.

  2. Stratify Based on Risk:

    • High-Risk Stigmata: Mural nodules ≥5 mm, MPD ≥10 mm.

    • Worrisome Features: MPD 5–9.9 mm, new-onset diabetes.

  3. Follow Management Path:

    • High risk: Surgical resection.

    • Worrisome: EUS-FNA for further evaluation.

    • Low risk: Surveillance every 6–12 months.

Surgical and Non-Surgical Management

General Principles

  • Surgery indicated for symptomatic or high-risk PCN.

  • Conservative management for benign types (e.g., SCN).

Surgical Techniques

Procedure

Indication

Pancreaticoduodenectomy (Whipple)

Main duct IPMN or malignant transformation.

Distal Pancreatectomy

Resectable lesions in body or tail.

Parenchyma-Sparing Surgery

Low-risk lesions or borderline cases.

Follow-Up Recommendations

Type

Interval

Duration

IPMN (low risk)

Every 6–12 months

Lifelong surveillance.

MCN (post-surgery)

Annual imaging

2–5 years.

SCN (benign)

None after 1 year if asymptomatic.

Discontinued.

Table: Comparison of Key Imaging Features

Cyst Type

Imaging Findings

Key Differentiators

IPMN

Ductal dilation, mural nodules.

Main duct or branch duct types.

MCN

Septations, peripheral calcifications.

Ovarian stroma in histology.

SCN

Microcystic, honeycomb appearance.

Glycogen-rich epithelium.

Pseudocyst

Homogeneous fluid-filled collections.

History of pancreatitis.

References

  1. European Study Group on Cystic Tumours of the Pancreas. European Evidence-Based Guidelines on PCN. Gut, 2018. Full Text.

  2. Sahora K, et al. Risk of Malignancy in IPMN. Gut, 2013. DOI Link.

  3. Tanaka M, et al. International Consensus Guidelines 2017 for PCN. Pancreatology, 2017.