recently , the detection of cystic lesions in the pancreas has greatly increased because of the wide use of high - resolution diagnostic imaging techniques.1 in contrast to solid tumors which are usually ductal adenocarcinomas , which have a very poor prognosis , most cystic lesions of the pancreas are either benign or low - grade malignancies ; thus , it is relatively easy to perform curative resection for them.2 therefore , cystic and intraductal tumors of the pancreas consist of an essential category with a challenging differential diagnosis.3 pancreatic squamoid cyst is defined as a lesion with cyst - like dilated ducts that are lined by non - keratinized squamous epithelium , and it is a recently recognized type of cystic lesion of the pancreas.2 we herein present a case of a patient with a pancreatic squamoid cyst who underwent laparoscopic resection .
a 60-year - old woman who underwent abdominal computed tomography ( ct ) for a routine health check - up was found to have a 1.8-cm cystic lesion in the tail of the pancreas .
her abdomen was soft and flat , and no tenderness or rebound tenderness was observed .
there was no evidence of pancreatitis . both the serum carcinoembryonic antigen ( cea ) and carbohydrate antigen 19 - 9 ( ca19 - 9 ) levels were normal .
a dynamic ct of the pancreas showed multiple cystic lesions in the tail of the pancreas and the largest cystic lesion showed a lobulated contour without communication with the pancreatic duct .
there were no indications of invasion into the surrounding tissues or dilatation of the main pancreatic duct ( fig .
magnetic resonance cholangiopancreatography revealed a 2.2-cm round cystic lesion in the tail of the pancreas which had no communication with the main pancreatic duct .
endoscopic ultrasonography revealed a 2.21.3 cm - sized cystic lesion and a 52.5 mm - sized mural nodule ; the septation within the cyst and the cyst wall was thin ; and the cyst was well - demarcated from the surrounding tissues .
the pancreas showed normal parenchymal echogenicity and the main pancreatic duct had a normal caliber ( fig .
we diagnosed the cystic lesion as an intraductal papillary mucinous neoplasm . to treat this lesion
, we performed laparoscopic spleen - saving distal pancreatectomy . during the operation , the cystic lesion , approximately 3 cm in diameter ,
was found arising from the border between the body and tail of the pancreas without any infiltration into the surrounding tissues .
most of the lesion was located within the pancreatic tissue , and its border was well - defined .
the patient showed the usual routine postoperative course and was discharged 10 days after surgery .
the patient quickly returned to her normal activities . on examination of the resected specimen ,
the cystic lesion of the pancreas ( 21.81.5 cm ) was multi - locular with thin septa ( fig .
a well - defined , oligo - locular cystic mass was in the pancreatic tail without a solid portion .
inner surface of the cyst was smooth and glistening and the cyst contained serous fluid .
histologic examination revealed that the cysts had linings ranging from flat squamoid cells to transitional cells with non - keratinization ( fig .
the epithelia of the cysts reacted negatively with muc 1 and muc 6 ( a marker for intercalated duct centroacinar cells ) , and positively with ck7 and p63 , and negatively with inhibin .
in 2007 , othman et al reported on 6 cases of cystic lesions with distinctive morphologic , immunophenotypic , and clinical characteristics , and proposed the term squamoid cyst of the pancreatic ducts to refer to these types of lesions.2 they mentioned that this type of cystic lesion typically resulted from uni - locular cystic dilatation of the ducts and had variable linings ranging from attenuated , flat , non - stratified squamous to transitional and stratified squamous epithelium , without a cornified layer or parakeratosis.2 however , no tall - columnar mucinous cells or acinar cells are evident in a squamoid cyst.1 the squamoid cyst of the pancreas is characterized by a flat , transitional , or squamous epithelium , and a p63 expressing basal and parabasal cell component .
kurahara et al mentioned that the microscopic version of this lesion is a relatively common incidental finding in the pancreas , and these , along with the expression of muc 1 and muc 6 , suggest that the process originates from the entroacinar / intercalated ductal system.1 however , the surface cells were negative for muc1 and muc6 in our case .
so we suggest that the immunophenotyping of the squamoid cyst should be studied further , especially from the point of view of the expression of muc1 and muc6 .
the expression of p63 in the cells forming the basal region is essential because p63 is a transitional / squamous cell marker and is not detected in the normal pancreas or in non - squamous neoplasms .
the surface cells were negative for muc1 and muc6 ( markers present in intercalated duct cells ) in this case .
thus , we were able to determine that squamoid cysts can be diagnosed without muc1 or muc6 being expressed .
there are other types of squamous - lined cysts of the pancreas , such as lymphoepithelial cysts , epidermoid cysts within an intrapancreatic accessory spleen , and dermoid cysts.4 lymphoepithelial cysts are lined by well - differentiated stratified squamous epithelium surrounded by a band of dense lymphoid tissue.4 epidermoid cysts within the intrapancreatic accessory spleen are lined by attenuated squamous cells , usually non - stratified , surrounded by normal - appearing splenic tissue.5 dermoid cysts are morphologically similar to teratomas seen in other sites .
the presence of adnexa - type elements ( sebaceous glands , hair , etc ) is more typical of dermoid cysts.6,7 these cystic lesions of the pancreas are thought to be all benign .
clinically , it is important to distinguish squamoid cysts of the pancreatic ducts from mucinous cyst - forming neoplasias , especially mucinous cystic neoplasms and intraductal papillary mucinous neoplasms.2 in contrast to squamoid cyst of the pancreatic ducts , which appears to be a benign lesion , these mucinous lesions have the risk of malignant transformation and have the potential to progress to invasive adenocarcinoma .
however , the differential diagnosis of pancreatic cystic lesions is not easy because the radiologic and clinical findings are not specific .
kurahara et al mentioned that tumor markers ( cea and ca19 - 9 ) may be high in squamoid cysts of the pancreas.1 we investigated 5588 patients who underwent a pancreatic biopsy or pancreatic resection from 2009 to 2012 in our institution , and found 7 cases of squamoid cysts of the pancreas . there were no connections to the main pancreatic duct and no solid portion in any of the cases .
the levels of cea , ca19 - 9 and ca72 - 4 were 1.860.91 ng / ml , 19.5526.9 u / ml , 2.570.23 , respectively .
there was one patient whose ca 19 - 9 was 76.6 u / ml , but this was not a specific finding because a pancreatic intraepithelial neoplasia was also found in her pancreas biopsy report.8 thus , we suggest that tumor markers can be an important method to use in the differential diagnosis .
cea is a very accurate tumor marker for diagnosing mucinous pancreatic cystic neoplasms , although the accuracy of this marker and the cut - off level vary among laboratories.9,10 in conclusion , squamoid cyst of the pancreas is a very rare disease , and it has been proposed only recently as a distinct pathologic lesion .
however , the diagnosis of squamoid cyst will increase due to improvements in imaging techniques such as ct scanning and magnetic resonance imaging .
this lesion is regarded as a benign entity , thus an extended operation should be avoided and resection of the lesion can be performed minimally .
 squamoid cyst of the pancreas is a very rare disease and it has been proposed only recently as a distinct pathologic lesion . 
 we herein present a case of pancreatic squamoid cyst in a patient who underwent laparoscopic resection . 
 a 60-year - old woman had an abdominal computed tomography ( ct ) scan for a routine check - up , and a multi - cystic lesion of 1.8-cm in size was incidentally found in the tail of the pancreas . 
 biochemical laboratory tests were within normal limits . 
 at first , we presumed that the most likely diagnosis of the cystic lesion was an intraductal papillary mucinous neoplasm . to treat this lesion 
 , we performed laparoscopic spleen - saving distal pancreatectomy . 
 the patient showed the usual routine postoperative course and she was discharged 10 days after surgery . on examination of the resected specimen , a well - defined 
 , oligolocular cystic mass was found in the pancreatic tail , without a solid portion . 
 histologic examination revealed that the cysts had linings ranging from flat squamoid cells to transitional cells with non - keratinization . 
 after immunohistochemical staining , the final diagnosis was confirmed to be squamoid cyst of the pancreas . 
 this lesion appears to be regarded as a benign entity , thus an extended operation should be avoided and resection of the lesion can be performed minimally . 