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Page 2 of 11 Jalal et al. J Cancer Metastasis Treat 2023;9:11 https://dx.doi.org/10.20517/2394-4722.2022.122

[3]
pancreatic cysts can be cancerous . The estimated risk of developing pancreatic cancer after seven years is
[4]
3% . The estimated prevalence of asymptomatic pancreatic cysts is 1.8% for patients older than 45 years .
[4]
The management of pancreatic cystic lesions (PCLs) often poses a dilemma. Some PCLs carry a high risk of
malignant transformation, whereas other cysts are benign with a negligible risk of malignant
transformation . Differentiating between malignant and non-malignant PCLs is crucial for future
[5]
management . Another challenge in the management of PCLs is distinguishing cysts that need close
[6]
monitoring from others for which the patient could be safely discharged.

Pathologically, PCLs include a heterogenous group of cysts, all of which have diverse clinical, radiological,
and pathological features, Table 1 and Figure 1. Cysts like lymphoepithelial cysts, pseudocysts, and serous
cysts are considered benign PCLs. Mucinous pancreatic cysts refer to intraductal papillary mucinous
[10]
neoplasms (IPMNs) and mucinous cyst neoplasms (MCNs) which are regarded as premalignant . IPMNs
are characterised by the intraductal papillary proliferation of mucin-producing cells, which results in the
[11]
cystic dilatation of pancreatic ducts . They are further divided into main-duct IPMNs (MD-IPMNs),
branch-duct IPMNs (BD-IPMNs), and mixed-type IPMNs.

Some pancreatic tumours exhibit cystic degeneration. These include solid pseudopapillary neoplasms, cystic
neuroendocrine tumours, and ductal adenocarcinomas . Individuals who have an IPMN are at an
[12]
increased risk of developing cancer, with 57%-92% of malignant transformations seen in MD-IPMNs and
6%-46% in BD-IPMNs. Certain clinical features, such as jaundice, weight loss, and obstructive liver blood
tests, and imaging features such as a dilated main pancreatic duct (MPD) diameter > 10 mm and/or mural
[13]
nodules indicate a high risk of progression to malignancy .
There are certain well-recognised worrisome features that raise the suspicion of an underlying malignant
potential. These include a cyst size ≥ 3 cm, enhanced mural nodules > 5 mm, thickened (enhancing) cyst
walls, a main pancreatic duct (MPD) calibre > 5 mm, abrupt changes in the MPD calibre with distal
pancreatic atrophy, associated lymphadenopathy, elevated serum CA19-9, and a rapid rate of cyst growth
> 5 mm/year .
[14]
Several studies have followed up on patients with pancreatic cysts to assess malignant transformation
[Table 2] [15-24] . Hisada et al. concluded that patients with an IPMN had significantly increased risks of
pancreatic cancer and related mortality in comparison with these risks for the general population of
[15]
Japan . Lawson et al. followed up with 767 patients, of which 78% had BD-IPMN and were originally
referred for EUS evaluation; they revealed that 6% had pancreatic cancer . Lee et al. found that malignant
[16]
changes in BD-IPMNs were associated with the presence of a mural nodule . Another study on cyst sizes
[17]
< 6 cm with a longer follow-up period found the overall risk of cancer to be 5% with a 5-year survival rate of
[18]
86% . For smaller cyst sizes, Nougaret et al. found no development of cancer in patients whose initial
lesion sizes were < 2 cm on follow-up .
[19]
METHODS OF DIAGNOSING PANCREATIC CYSTS
CT and MRI scans
CT and MRI are the most used techniques in diagnosing and assessing pancreatic cysts. Although CT and
MRI scans can be useful in the initial diagnosis and management of pancreatic cysts , alone, neither is
[25]
adequate for fully characterising PCLs or for differentiating mucinous cyst neoplasms from macrocystic
serous cyst neoplasms .
[26]