ipmn - intraductal papillary mucinuous neoplasm

1. Intraductal Papillary Mucinous Neoplasm
(IPMN) of Pancreas
|
Presenter: Rohan Kumar
(DrNB Resident, Fortis Jaipur)

2. Classification of pancreatic cystic neoplasm

4. Introduction
• IPMN
 Papillary growth in ductal system
Thick mucin production
Risk of malignant transformation (adenoma-carcinoma sequence)
Cells of origin: Ductal epithelium
Cystic dilatation of main/branched pancreatic duct

5. Introduction
• 6th-7th decade of life; males predominantly
• Incidence –
<10% of all pancreatic neoplasms
0.5% of pancreatic neoplasms detected at autopsy
7.5% of clinically detected pancreatic neoplasms
16.3 – 25% of surgically resected pancreatic tumors
50% of incidentally detected pancreatic cysts

6. Introduction
• Site: Head of pancreas (M/C)
• Diagnosis is delayed as
Asymptomatic mainly and presentation is similar to pancreatitis in others
Preoperative differentiation of benign and malignant is difficult
• Resection of non invasive tumors – favourable prognosis
• Invasive neoplasms have poor survival despite curative resection

7. Etiology and Pathogenesis
• No definite genetic/familial predisposition
• Hypothesis: Adenoma – carcinoma sequence
• Most IPMN: MUC2 expression – excessive mucin production
MUC 1 not expressed
• Mixed IPMN: both MUC1 and 2 expression
• also PCNA; tp53; VEGF expression in invasive ones
• GTPase kRAS mutation – inactivation of CDK2A (p16) inhibitor and tp53

8. Genetic difference between IPMN and
pancreatic cancer
• SMAD4/DPC4 expression inactivated in more than half of pancreatic
adenocarcinoma but preserved in non invasive IPMN
• lost only in 10% of colloid cancers in background of intestinal type of
IPMN
• GNAS mutations exclusively present in IPMN and absent in all other cystic
neoplasm and adenocarcinomas not associated with IPMN

9. Pathology
• Main duct-IPMN (MD-IPMN): segmental or diffuse dilation of the MPD of >5
mm and in the absence of other cause of obstruction
• 5-9mm : “Worrisome”
• ≥ 10mm : “High-risk”
• Branched duct IPMN (BD-IPMN): pancreatic cysts >5mm communicating with
MPD
• Mixed IPMN: features of both subtypes
• Location: Head (50%); tail (7%); uncinate process (4%); rest (39%)

10. Histology
• Based on cytoarchitectural features and immunophenotypes:
• Intestinal (18 – 36%) : CDX2 and MUC2 expression
• Gastric (49 – 63%) : MUC5AC positive; MUC1 negative
• Pancreatico-biliary (7 – 18%) : invasive CA (tubular variant), aggressive
• Oncocytic (1 – 8%) : MUC6 positive, limited invasive capability
• Prognosis: Colloid variant >>tubular CA

11. Differential diagnosis
• Mucinous cystic neoplasms: presence of ovarian type stroma, no ductal
communication; exclusively in young women
• Retention cysts: unilocular, lined by normal duct epithelium without atypia
• PanIN (pancreatic intraepithelial neoplasm): premalignant, flat micro-papillary
lesions <5mm size, MUC2 negative and MUC5AC positive
• ITPN (intraductal tubulo-papillary neoplasm): solid intraductal growth with
necrotic foci and no mucin
• Chronic pancreatitis
• Pancreatic pseudocysts/ simple cysts

12. International classification system
•Low dysplasia (adenoma)
•Intermediate dysplasia (borderline)
•High grade dysplasia (carcinoma in situ)
•Evolution to carcinoma is slow (3 – 6.4 years)
•Malignant IPMN with LN mets (22%) – favourable prognosis
compared to ductal adenoCA
Non-
invasive
Invasive

13. Changes in who classification
5

14. Classification
• Based on site and extent:
Main duct IPMN (MD-IPMN)
Branched duct IPMN (BD-IPMN)
Mixed
• Morphological pattern of duct
dilatation
• Diffuse
• Segmental
• Side branch
• Multifocal cysts with ductal
communication

15. MD-IPMN
• Diffuse/segmental dilatation of MPD, filled with mucin
• Dilatation due to obstruction by growth, mucus production by head mass or diffuse
involvement of duct itself
• Head>>Tail
• Segmental: body and tail >> head
• Chronic obstruction with viscid mucin/mural nodule – fibrotic pancreas
• Mural nodule, tumor ≥30mm, MPD diameter ≥12mm : increased malignant
potential (91%)
• Incidence of malignancy: 57-92%

16. BD-IPMN
• Cystic dilatation of ≥1 duct; filled with solitary/multiple tumors and/or viscid
mucin
• Side branch ectasia – usually head and uncinate process
• often confused with pseudocysts, simple cysts, and serous cystadenoma: appear
similar on imaging
• Large tumors – compress CBD and MPD – jaundice
• Large mural nodule : malignant potential
• Incidence of malignancy: 6 – 46%

17. Mixed type
• Advanced form of the branch type, in which IPMN has spread to the MPD
OR
• End result of the MPD type involving the BD as well
• MPD contains papillary growth of columnar epithelia of various degrees of
dysplasia that produce excessive mucin
• BD-IPMN with excessive mucin production – dilated MPD : falsely labelled
as mixed IPMN

18. Clinical presentation
• Epigastric discomfort/pain (70-80%)
• Nausea and vomiting (11-21%)
• Backache (10%)
• Weight loss (20-40%) – decreased food intake due to pain at meals
• Diabetes – pancreatic insufficiency due to persistent occlusion of MPD – Hyper-amylasemia
• Jaundice – compression of CBD, obstruction by mucin/mural nodule
• Acute pancreatitis (20%)
• Asymptomatic – tail and body lesions
• Inter-visceral fistulae – mechanical pressure/inflammation & autodigestion/direct invasion

19. Diagnosis
• USG<<CT/MRI
• MRCP – initial investigation of choice
• CT: delineation of ≥1 cystic dilatation of MPD/BD
• Distending duodenal lumen with water – localizes the protruding papilla
• Deposits of calcium in the mucin
• Increased parenchymal thickness with papillary proliferation – invasive tumor
• Communication of cyst with duct establishes diagnosis
• Tumor size >3cm with mural nodule, LN involvement, MPD>12mm : malignant

21. • ERCP:
• Ductal system and cystic communication
• MPD and its branches
• Filling defects with obstruction by mucin/nodule
• Gaping ampulla with extrusion of mucin – fish mouth appearance
• Disadvantage: invasive procedure

22. MRCP AND EUS
• MRCP:
• More sensitive than ERCP
• No operator dependency and non
invasive
• HIGH signal intensity – better
delineation of side branch IPMN
even in presence of obstruction
• Useful in post-operative followups
• EUS: diagnostic features of IPMN
• Dilatation of MPD
• Hypoechoic thickening of duct wall
• Mural nodules
• Papillary projections
• Parenchymal atrophy
• 75% sensitivity and 94% specificity
• Analysis of cyst fluid for cytology, extracellular
mucin and CEA

23. INDICATION FOR EUS

24. .
• Peroral pancreatoscopy
• Assessment of mucin secretion
• nature and location of mural nodules
and their biopsy can be established
• MD-IPMN: fish-egg appearance of
papillary neoplasm, granular or
polypoidal mucosa
• BD-IPMN: reveal mucin in the MPD
• Limited expertise and operator
dependency
• (FDG-PET)/CT scan
• differentiating between benign and
malignant IPMN with mural nodules
• role in routine management of IPMN
is still to be established
• sensitivity, specificity, positive
predictive value, negative predictive
value, and accuracy were found to be
77.8%, 100%, 100%, 77.8%, and
87.5%, respectively

25. Recenty study by F Azari et al concludes that
Diagnosis of combined type IPMN on high-quality
imaging is highly predictive of final pathology.
Endoscopic interventions subject patients to additional
procedural complications but often add little and may
not improve accuracy.

26. Preoperative predictors of malignancy
Clinical variables
• jaundice and its worsening form, or the new onset of diabetes mellitus
• Elevated CEA: a marker that distinguishes mucinous from non-mucinous cysts.
cutoff value of ≥192-200 ng/mL: 80% accurate diagnosis of a mucinous cyst
• Seven predictors in BD-IPMN: Jaundice, pancreatic head tumor, MPD size >5 mm,
mural nodules >5 mm, serum CA 19-9 level, positive cytology in pancreatic juice, and
CEA levels in pancreatic juice >30 ng/mL
Mural nodule size >5 mm and CEA levels in pancreatic juice of >30 ng/mL -
independent factors with PPV of 100% and NPV of 96.3%

27. Preoperative predictors of malignancy
Radiological variables
• Mural nodules, abnormal contrast enhancement of the ductal walls, mural nodules
>3 mm, cyst size >3 cm, and dilated MPD >10mm (92% specificity)
• Other findings: large side branch tumors, papillary bulging, CBD dilatation, large
number of tumors, solid components, calcified ductal content, invasion to adjacent
organs, enlarged peripancreatic lymph nodes, and presence of liver lesions

28. Workup for cystic lesions of the pancreas
• Initial investigation of choice in evaluating IPMN should be pancreatic
protocol MRI/MRCP (CT only when MRI is not available) or EUS.
• ERCP, cystic fluid analysis, and pancreatoscopy are considered in cases
where there is difficulty in establishing the diagnosis or in ruling out
malignancy
• Staging of the invasive carcinoma is by protocols of the American Joint
Committee on Cancer/ TNM Classification of Malignant Tumors
(AJCC/TNM)

29. Workup for cystic lesions of the pancreas
• “Worrisome features”
• cyst of ≥3 cm
• thickened enhanced cyst walls
• MPD size of 5-9 mm
• nonenhanced mural nodule
• abrupt change in the MPD caliber with
distal pancreatic atrophy,
• lymphadenopathy
• Asymptomatic cases: Evaluated by EUS
• Symptomatic: resected and followed up
• “High-risk stigmata”
• obstructive jaundice in a patient with
a cystic lesion of the pancreatic head
• enhanced solid component
• MPD size ≥10 mm
• Treatment: Resection

30. Association with other malignancies
• Rate of association with extra-pancreatic organs malignancy: 10-40%
• In a multicenter cohort study of 92 patients with IPMN, extra-pancreatic
malignancy was found in 23.6% cases
• Gastrointestinal cancer: Asia
• Skin, breast, and prostate cancers: United States
• No screening recommendations for detecting extra-pancreatic malignancies at
present

31. Management
• Surgical outcome is far superior to PDAC – indolent behaviour and late metastasis
MD-IPMN
• Mean frequency of malignancy is 61.6%, invasive IPMN is 43.3%, low 5-year survival rates (31-
54%)
Indication of resection
• Invasive MD-IPMN: patient fit; surgical resection with LN-ectomy
• Benign IPMN: observe
• MPD diameter 5-9mm (worrisome feature): no immediate resection; evaluate and observe while
some studies advice resection if >6mm, in fit patient
• Criteria for resection: symptomatic, MPD >10mm, mural nodule >5mm, positive cytology and
CEA>110ng/mL in aspirated fluid

33. Management
BD-IPMN
• mean frequency of malignancy in resected BD-IPMN is 25.5%
• mean frequency of cancer is 17.7%
• mostly occur in elderly patients with an annual malignancy rate of 2-3%
• New high-risk factors: rapidly increasing cyst size and high-grade atypia
Indication for resection
 Symptomatic
• Younger (<65yrs) with size >2cm: resect, owing to cumulative risk of malignancy
• size>3cm with mural nodule and positive cytology: resect
• Otherwise observe

35. Extent of resection
• Based on the location and extent
• Pancreaticoduodenectomy with lymphadenectomy: Invasive MD-IPMN
of the head, the neck, or the uncinate process
• Distal pancreatectomy: IPMN of body and tail of the pancreas
• Total pancreatectomy:
• Exceptional cases when IPMN diffusely involves the whole gland and proximal IPMN
extends through the body and the tail

36. Extent of resection
• Partial pancreatectomy: margin assessment by frozen section and further resection in
• high-grade dysplasia or
• invasive carcinoma
• Following total pancreatectomy for invasive IPMN, the overall disease recurrence
(disseminated>isolated) rate is 12-68%
• Prophylactic total pancreatectomy: No role
Role of Limited resection or focal nonanatomic resection???
• excision, enucleation, and uncinectomy for BD-IPMN without suspicion of malignancy
• Risks: mucin leakage – pseudomyxoma peritonei; pancreatic fistulae and recurrence –
residual neoplasms

37. On table assessment of extent of resection
• Diffuse dilatation of MPD on preoperative imaging can be due to:
mucus plugs, tumor obstruction, or diffuse involvement
• Intraoperative ultrasonography, pancreatoscopy, intraoperative frozen section
assessment of resected margin
• Low/moderate dysplasia – no further resection required
• High grade dysplasia/invasive tumor – resect until margin negative
• Exuberant papillary nodules – no resection v/s total pancreatectomy

38. Role of mucosal ablation by ethanol injection
under EUS guidance
• Indication:
• cystic lesions that show no communication with the MPD
• those who refuse surgery or
• high-risk surgical candidates
• Concerns:
• insufficient ethanol infiltration
• impossible imaging surveillance after cyst collapse
• Applicability, adequacy and long term outcomes not available yet
• Presently, under research

39. Role of adjuvant therapy in invasive IPMN
• Better survival rate when treated with gemcitabine-based adjuvant
chemotherapy
• Significant disease-free survival benefit in both node positive and node
negative subgroups
• Significant overall survival benefit in patients with node involvement

40. IPMN versus PDAC
• IPMN:
• Presents early
• Less chances of nodal involvement (45.4% versus 62.9%)
• Less perineural (49.2% versus 76.5%) and vascular invasion (25.2% versus 45.7%)
• Likelihood of extra-pancreatic spread: 27.6% versus 94.3%
• Better overall 5 year survival (34.5% versus 12.4%)

41. Prognosis, recurrence and surveillance
• Overall 5-year survival is 36-77% and for noninvasive IPMN is from 77% to 100%
• 5-year survival rate following surgical resection of invasive IPMN is 27-60%
• Poor prognostic factors:
• invasive carcinoma
• type of invasive component (tubular is worse than colloid)
• lymph node involvement
• vascular invasion
• Surgical margin involvement
• presence of jaundice

42. Prognosis, recurrence and surveillance
• Overall recurrence rate for IPMN varies from 7% to 43%
• Following total pancreatectomy for invasive IPMN, the overall disease recurrence rate
is 12-68%
• Risk of recurrence in both invasive and noninvasive IPMN, making follow-up
mandatory
• Repeat resection for isolated recurrence in the pancreatic remnant – good results
• The recurrence in the form of disseminated disease (3.4-44%) is higher than isolated
pancreatic remnant recurrence (0-15%)

43. Follow up

44. .
According to recent study by G. Marchegiani et al
The risk of developing pancreatic malignancy in presumed BD-IPMN
without WF or HRS after 5 years of surveillance is comparable to
that of the general population depending on cyst size and patient
age. Surveillance discontinuation could be justified after 5 years of
stability in patients older than 75 years with cysts < 30 mm, and in
patients 65 years or older who have cysts ≤ 15 mm.

45. Conclusion
• Natural history and pathology of IPMN is still incomplete
• If untreated, some of them may follow the dysplasia-carcinoma sequence, and progress into
invasive carcinoma
• Recent guidelines suggest a lowering of the MPD diameter to >5 mm as a criterion
for characterizing MD-IPMN
• Management of MD-PMN in surgically fit patients would warrant resection
• In patients with BD-IPMN, a more conservative approach is practiced
• The standard treatment for invasive IPMN would be pancreatectomy with lymph node dissection,
while limited resection is appropriate for noninvasive lesions
• Role of adjuvant therapy in invasive IPMN is evolving
• Overall 5-year survival of noninvasive IPMN is good, and moderate in invasive despite surgical
resection

46. Thank You