Kyoto guidelines

The Tanaka criteria, also referred as Fukuoka consensus guidelines, is a classification system for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs).

The prior international consensus guidelines (2006) were referred to as the Sendai criteria. This later evolved into the Fukuoka consensus guidelines (2012).

Classification

• branch duct IPMN (BD-IPMN)
• main duct IPMN (MD-IPMN)
  • higher frequency of malignancy
  • dilatation of the main duct >5 mm without other cause for obstruction
    • 5-9 mm: "worrisome feature"
    • ≥10 mm: "high-risk stigmata"
• mixed-type IPMN: appears like an advanced branch duct IPMN with main pancreatic duct dilatation (>5 mm)
  • higher frequency of malignancy, similar to the main duct type

High-risk stigmata

• enhancingEnhancing solid component
• mainMain pancreatic duct ≥10 mm
• obstructiveObstructive jaundice

Worrisome features

• cystCyst ≥3 cm
• thickenedThickened and enhancing cyst wall
• nonenhancingEnhancing mural nodule
• mainMain pancreatic duct 5-9 mm
• lymphadenopathyLymphadenopathy
• Abrupt change in calibre of pancreatic duct with distal pancreatic atrophy
• Cyst growth rate ≥5 mm in 2 years

Histological subclassificationSubclassification

• gastric type: the majority of BD-IPMNs
• intestinal type
• pancreaticobiliary type
• oncocytic type

Treatment and prognosis

• resectionResection
  • allAll main duct IPMNs
  • allAll other IPMNs with high-risk stigmata
  • allAll MCNs
• endoscopic ultrasound (EUS)
  • cystsCysts with worrisome features
  • allAll cysts ≥3 cm without worrisome features
    • if inconclusive, then close surveillance with alternating MRI and EUS every 3-6 months
    • strongly consider surgery in young patients
• optimal

Cyst fluid analysis is optional in a centre with expertise in EUS fine needle aspiration.

Surveillance

Optimal imaging surveillance strategies for suspected BD-IPMNs <3 cm and without worrisome features is unclear, but the yearly incidence of transformation to pancreatic cancer is estimated at 0.4-1.1% per year

• largest cyst <1 cm: CT or MRI/MRCP in 2-3 years
• largest cyst 1-2 cm: CT or MRI/MRCP annually for 2 years, then lengthen interval if no change
• largest cyst 2-3 cm: EUS in 6 months, the lengthen interval alternating MRI with EUS as appropriate
  • consider surgery in young patients

Cyst fluid analysisn.b. The American Gastroenterological Association recommends stopping surveillance after 5 years if no significant change is optionalobserved or if a cyst is resected and found to be benign. This is not a recommendation explicitly shared in a centre with expertise in EUS fine needle aspirationthe Fukuoka 2017 update.