Editing Pancreatic lesions (section)

=== '''Intraductal papillary mucinous neoplasms (IPMN)''' ===

*** Mucinous epithelial neoplasms which arise from pancreatic ducts
*** Pathophysiology
**** Composed of mucin-producing columnar cells
**** Classified as low-grade, moderate, and high-grade dysplasia; and presence or absence of invasive malignancy
**** Four subtypes: 
***** Gastric
****** Primarily BD-IPMN
****** Typically low-grade
***** Intestinal
****** Most common type of MD-IPMN
****** Found in pancreatic head
***** Pancreaticobiliary
****** Typically involves main duct, in pancreatic head
****** Greatest likelihood of malignancy
****** Poor prognosis
***** Oncocytic
*** Classification
**** Main duct
***** Diffuse or segmental involvement of the main PD, with radiographic findings of main duct >5mm without any other cause of obstruction
***** Risk of high-grade dysplasia or invasive carcinoma (30-50% risk of invasive cancer at time of presentation)
**** Branch duct
***** Involve smaller side branches but not main duct
***** Typically occur in younger patients
***** More common than main duct (10:1)
***** Can occur anywhere in pancreas
***** Often multifocal (multiplicity of cysts favours BD-IPMN)
***** Lower risk of malignant transformation
***** Overall risk of invasive malignant disease is 10-15% (2-3% per year)
**** Mixed
***** Side branch IPMNs that extend into the main duct, and often lead to upstream dilation
***** Behave clinically like main duct lesions - 30-50% risk of invasive malignancy at presentation
*** Clinical presentation
**** Most commonly 50-70yo
**** Mostly found incidentally
**** If symptoms are present, they are non-specific
**** Can develop pancreatitis-like symptoms, especially with MD-IPMN
*** Diagnosis
**** Imaging
***** CT and MRI are equivalent for tumour type, location, development of additional lesions, lymph node and organ mets, invasion
***** MRI better for ?septae and ?mural nodules and ?solid components and more accurately defines involvement of main PD
**** Endoscopy
***** Fish-mouth sign - pathognomic
*****
***** Other features below on EUS
*** Management
**** MD-IPMN or mixed-type IPMN: Resect if medically fit
**** BD-IPMN: Risk stratification with Fukuoka guidelines
***** '''High-risk stigmata''' (surgery recommended if any one of these)
****** Enhancing mural nodule >5mm
****** Main duct size >=10mm
****** Obstructive jaundice
***** '''Worrisome features''' (needs EUS if any of these)
****** Size >3cm
****** Main PD size 5-9mm
****** Abrupt change in calibre of PD with distal pancreatic atrophy
****** Symptoms other than jaundice
****** Thickened, enhancing cyst walls
****** Enhancing mural nodule <5mm
****** ''Extra worrisome features according to Sabiston: clinical pancreatitis, elevated CA 19-9, cyst growth of >5mm over two years''
***** '''EUS/histo features:''' (operate if any of these)
****** Definite mural nodule/s >=5mm
****** Main duct features suspicious for involvement
****** Cytology suspicious or positive for malignancy
***** Other factors
****** FHx pancreatic cancer (two or more first-degree relatives)
****** Inability to tolerate surgery
****** Patient preference
**** Operations
***** Extent of resection depends on location and pathologic features
***** BD-IPMN - target the lesion of concern with partial pancreatectomy
***** MD-IPMN - harder to determine the extent of microscopic abnormality within the duct. Generally right-sided pancreatectomy with frozen section, with total pancreatectomy for those with HGD/cancer at margin.
*** Prognosis
**** Survival 77% 5 years for non-invasive IPMNs
**** 43% for invasive IPMNs
*** Surveillance
**** See below
*** Extra-pancreatic malignancy
**** High-risk for cancer in other places
**** Frequent locations include breast, colon and prostate