RADIOLOGICAL EVALUATION OF CYSTIC LESIONS OF PANCREAS

1. CYSTIC PANCREATIC TUMOURS
Dr.I.Gurubharth MD PhD Dr.Pooja MD

2. CYSTIC PANCREATIC TUMOURS
 The commonest cystic mass within the pancreas is a pseudocyst
(demonstrating a high amylase level following FNA)
 If there is a low amylase level then a cystic tumour has to be
considered:
 Serous microcystic neoplasm
 Mucinous macrocystic neoplasm

3. Cystic neoplasms
Unilocular
Intraductal papillary mucinous neoplasms (IPMN)
Serous cystadenoma
Macrocystic: multilocular
Mucinous cystic neoplasm
Intraductal papillary mucinous neoplasms (IPMN)
Serous cystadenoma
Microcystic
Serous cystadenoma :usually head. 30% have a central scar
Cystic with a solid component
Macrocystic tumours can have solid component as well
pancreatic adenocarcinoma may undergo cystic degeneration (8%)

4. Intraductal papillary mucinous neoplasm (IPMN)
 This is a rare cystic low-grade pancreatic tumour arising from the
epithelial lining of the pancreatic ducts
 Excessive mucin secretion results in duct dilatation and obstruction
 Location:
pancreatic head (58%) > body (23%) > tail (7%)
 Slight increased frequency in male patients.
 The pathologic hallmarks of the lesion are
Diffuse or segmental dilation of the main or side branch
pancreatic ducts,
Intraductal growth of the mucin-producing epithelial lining cells,
Protrusion and dilation of the major and minor papilla with
mucus excretion

5. Main duct IPMN:
• High malignancy risk (invasive features in 50%)
• Surgical removal usually advocated
Branch duct IPMN:
• Lower malignancy risk (especially if < 3cm)
• Close follow-up advocated if < 3cm and no signs of malignancy

6. Radiographic features
 The characteristic feature is that these tumours communicate with
the pancreatic duct or branches, which helps to distinguish these
tumours from mucinous cystadenoma / cystadenocarcinoma which
do not.

7. Ultrasound
 Ultrasound demonstrates dilated ducts which appear hypoechoic.
Mural nodules and mucin globules may appear hyperechoic, and
difficult to separate from adjacent pancreatic parenchyma.
 Diffuse main duct type has appearances essentially
indistinguishable from chronic pancreatitis, with duct dilatation and
parenchymal atrophy

8. CT
 In some cases, the tumour is very localised and appears cystic.
 It can therefore be difficult to distinguish from
peripheral mucinous cystadenoma / cystadenocarcinoma unless
convincing communication with the duct system can be
demonstrated. They do not calcify.

9. Main duct IPMN (with dilatation of main duct >5 mm)
 Either segments of the pancreatic duct (or the entire duct) are dilated
and filled with low density (mucin thus water density) material
 Overlying pancreatic parenchyma may be thinned
 If proximal, the distal pancreatic duct may be dilated without direct
involvement (cystic neoplasms can have a similar appearance)
 Solid mural nodules are concerning for malignant transformation, and
appear as hyperdense nodules protruding into the mucin-filled dilated
ducts
 Enhancing nodules following administration of contrast are very
concerning
 Occasionally mucinous material can be seen to bulge out of a
dilated ampulla of Vater (uncommon but essentially pathognomonic)

10. Branch duct IPMN
 The majority of the gland is normal in appearance, except for a
single or multiple side branches demonstrating marked
dilatation
 Cystic mass-like appearance which often mimicks cystic
tumours of the pancreas
 Its appearance has been termed a bunch of grapes due to its
appearance microcystic variety has appearances similar
to serous cystadenomas, but again communication with the
main pancreatic duct is the key to correct diagnosis

11. Multifocal (around 8) non-enhancing low density lesions throughout the pancreas, some of
these communication with the pancreatic duct. Pancreatic duct is prominent in relationship to
lesions in the distal pancreatic tail, pancreatic neck and head. Background pancreas is
unremarkable with a single calcification. No lymphadenopathy.

13. MRI
• MRI appearances are similar to those seen on CT.
• Mural nodules appear hypointense compared to surrounding fluid and
mucin and enhance following administration of contrast.
• Mucin globules do not enhance and lie dependently within the duct.

14. Cystic lesion in the tail of pancreas, with a 'bunch of grape' appearance. It is
continuous with the main pancreatic duct.

15. Cystic lesion in the tail of pancreas, with a 'bunch of grape'
appearance. It is continuous with the main pancreatic duct.

16. ERCP
• Direct imaging of the pancreatic duct demonstrates variable
dilatation (segmental or diffuse or branch) depending on the
type.
• Polypoid mural tumour or amorphous mucinous luminal filling
defects may be identified.
• Mucinous material may be seen protruding from the ampulla of
Vater.

17. Predictors of malignancy
• Main pancreatic duct > 9mm
• Mural enhancing nodules
• Signs of invasion
• Thick septa
• Irregular wall

18. Treatment and prognosis
• Current consensus criteria recommend resection for main duct
IPMNs and varying treatment of branch duct IPMNs, ranging from
resection to surveillance, depending on high risk stigmata and
worrisome features.
• Patient co-morbidities and wishes clearly have a major impact on
the decision to operate.
• If the lesion is proximal (either segmental main duct or branch type)
then a Whipple procedure may be performed.
• If distal then a partial pancreatectomy suffices.
• Complete resection is curative.

19. Differential diagnosis
General imaging differential considerations include
1. Chronic pancreatitis
2. Mucinous cystadenoma / cystadenocarcinoma
should not appear to communicate with the main pancreatic
duct
3. Serous cystadenoma
should not appear to communicate with the main pancreatic
duct
appear similar to microcystic branch type IPMN
30-40% have central calcification

20. Serous cystadenoma of pancreas
Serous cystadenoma of the pancreas (or microcystic adenoma) is an
uncommon type of benign cystic pancreatic neoplasm.
Epidemiology
There is a recognised strong female predilection (M:F ~ 1:4)
middle age to elderly patients (>60 years of age).
Clinical presentation
Many patients are asymptomatic.
Some may present with pain, weight loss, jaundice or a palpable mass

21. Pathology
Pancreatic serous cystadenomas are benign neoplasms composed of
numerous small cysts that are arrayed in a honeycomb-like formation.
There can be significant variation in locule size (1-20 mm).
Most individual cysts are typically <10 mm .
Three morphological patterns have been described :
• Polycystic: 70%
• Honeycomb: 20%
• Oligocystic (macrocystic variant): <10% (cysts can be larger than 20
mm)
Lesions can be rather large at presentation (~5 cm).
Associations
von Hippel Lindau (vHL) disease can be multiple or diffuse and present at
younger age
Location
Lesions favour the pancreatic head.

22. Radiographic features
Plain radiograph
• nonspecific and will usually be normal
• may demonstrate amorphous central calcification overlying the
pancreas
Ultrasound
• Nonspecific hypoechoic mass in the pancreatic head region,
possibly with internal echoes indicating microcysts
(the oligocystic subtype may demonstrate individually identifiable
cysts )

23. CT
• Typically demonstrates a multicystic, lobulated mass in the
pancreatic head sometimes described as a 'bunch of grapes'
• The individual cysts are typically <20 mm in size and greater
than six in number (except for the oligocystic variety
• A characteristic enhancing central scar may be present which can
show associated stellate calcification (present in ~20% of cases)

24. Well demarcated lesion of the pancreatic head, containing multiple microcysts (1-2 cm)
filled with fluid and separated by fibrous septa with honeycomb appearance. The septa
show enhancement and a small central scar can be appreciated. The lesion is not in
communication with the duct of Wirsung

25. MRI
• Serous cystadenomas usually appear as a cluster of small cysts
within the pancreas.
• There is no visible communication between the cysts and the
pancreatic duct.
• Signal characteristics include
• T1: typically low signal
• T2: the central fibrous scar (if present) is low signal while cystic
components themselves are high signal
• T1 C+ (Gd): fibrous septa between them may enhance on delayed
contrast enhanced images
• Excluding the absence of communication with the main pancreatic
duct, visualisation of the lesion will not be facilitated by secretin
enhanced MRCP (SMRCP or MRCP-S)

26. Well demarcated lesion of the pancreatic head, containing multiple microcysts (1-2 cm) filled
with fluid and separated by fibrous septa with honeycomb appearance. The septa show
enhancement and a small central scar can be appreciated. The lesion is not in communication
with the duct of Wirsung.

27. The MRCP sequence reveals the mass to consist of tiny cystic spaces throughout.
The main duct is not dilated and does not appear to communicate with the mass.

28. Angiography
• May show enhancement due to hypervascular components.
Treatment and prognosis
• Most lesions are observed without treatment.
• They are benign lesions and do not recur once resected

29. Differential diagnosis
General imaging differential considerations on cross sectional
imaging include
• Intraductal papillary mucinous tumour (IPMN) of pancreas
communicates with pancreatic ducts
• Pancreatic pseudocyst
• Mucinous cystic neoplasm of pancreas (e.g. mucinous
cystadenoma)
calcification tends to be peripheral
usually unilocular
if multilocular type, individual cysts tend to be >20 mm in size

31. References:
1. Levine MS, Gore RM, Levine MS. Textbook of gastrointestinal
radiology.
2. Adam A, Dixon AK, Gillard JH, Schaefer-Prokop C, Grainger RG,
Allison DJ. Grainger & Allison's Diagnostic Radiology E-Book.
Elsevier Health Sciences; 2014 Jun 16.
3. Dahnert WF. Radiology review manual. Lippincott Williams &
Wilkins; 2017 Mar 9.
4. www.Radiopedia.org