solid pseudopapillary tumour ( spt ) of the pancreas is one of the rare found primary tumors of the pancreas , making up approximately 0.172.7% of cases .
there have been controversies regarding the terminology and according to its macroscopic and microscopic pathological characteristics over the years .
it has been given multiple descriptive names such as papillary - cystic tumour , solid cystic tumor , papillary epithelial neoplasm , solid , and papillary neoplasm , papillary tumour of the pancreas , or frantz 's tumor   until in 1996 the who pancreatic tumour working group recommended the use of the term solid pseudopapillary neoplasm .
one of its characteristics is that this tumour seems to preferentially affect mainly young women usually in the second or third decade of life .
extrapancreatic spt cases in the retroperitoneum , liver , omentum , and mesocolon have been published .
some of them were considered to arise from an ectopic pancreas [ 46 ] . to the best of our knowledge ,
an 18-year - old woman complaining of abdominal pain , nausea , and vomiting for one month was admitted to our hospital for further evaluation . she had no history of abdominal trauma or surgery , drug usage or smoking .
tumour markers ( alpha - fetoprotein , carcinoembryonic antigen , ca-125 , ca15 - 3 , ca19 - 9 , and ca72 - 4 ) of serum and other biochemical analyses were within normal limits . abdominal ultrasonography ( usg ) showed an encapsulated solid mass of 5  5.5  cm in diameter located on the subhepatic region displacing the second part of the duodenum laterally , and the computer tomography confirmed a well - encapsulated mass of 48  51  mm diameter located in the mesenteric region neighboring the superior mesenteric artery and vein , with no distinct separation from the head of the pancreas .
the patient then underwent surgery , and exploration revealed an encapsulated mass of 5  5  cm in diameter that was adherent to the mesentery of the transverse colon .
the tumor was not infiltrating the pancreatic tissue . no vascular invasion or lymph node metastasis
pathologic examination of biopsy material revealed small cells with uniform spherical nuclei with narrow eosinophilic cytoplasm and tumoral cells forming glandular structures ( figure 1 ) .
neuron - specific enolase ( nse ) , chromogranin , cd10 , cd99 , cd68 , lca , calcitonin , cea , ema , hmw ck , lmw ck , ck 7 , ki 67 , and synaptophysin antibody staining were negative ; however , the tumoral cells were stained remarkably with progesterone receptor antibody and vimentin ( figures 2(a ) and 2(b ) ) . in light of these findings ,
spt is a rare disease with a reported incidence of 0.13% to 2.7% of all pancreatic tumors , and cases often have been misunderstood .
the spt has usually occurred in young women during the second to fourth decades of life .
abdominal discomfort is the prevailing symptom associated in some cases with a palpable mass , anorexia , and weight loss .
the most common extrapancreatic sites are mesocolon , liver , retroperitoneum , or greater omentum [ 47 ] .
only four spt , developed from mesocolon , have been described previously ( table 1 ) .
the presence of ectopic pancreatic tissue is seen in all of these published cases [ 5 , 6 , 8 , 9 ] .
ishikawa et al .   described the first spt case arising from an ectopic pancreas in the mesocolon .
patient was 13-year - old girl , and 8-cm , well - encapsulated , and partly calcified tumor which protruded from the mesocolon was resected surgically . at the base of this tumor ,
small pancreatic tissues ( islet , acinar , and ductular cells ) were detected in the mesocolic tissue .
these four tumours ( table 1 ) tended to grow to a large size ( 60210  mm ) , usually occurred in young female patients ( only one was in a man ) , and produced similar clinical signs .
in all four published cases the tumour was found to be separate from the main pancreas at surgery . a case of spt arising in the omentum without pancreatic tissue
mentioned that the occurrence of a few spts in the retroperitoneal space outside the pancreas can be related to the localization of the genital ridge during embryogenesis   and speculated that spt might originate from genital ridge - related cells that were incorporated into the pancreas during organogenesis .
this theory might suggest one explanation for the occurrence of spt in the mesocolon in the presented case .
spt can be readily diagnosed by routine histologic examination , but accuracy of diagnosis may be improved with the help of immunohistochemical staining because such tumours are typically negative for cytokeratin , pancreatic enzyme markers , and endocrine markers but positive for vimentin , cd 10 , cd 56 , and alpha - antitrypsin [ 37 , 9 , 10 ] .
we encountered an extremely rare case of spt arising in the mesocolon without ectopic pancreatic tissue .
 a solid pseudopapillary tumour ( spt ) is an uncommon pancreatic tumour . 
 very rarely it has also been described outside the pancreas , usually arising from heterotopic pancreatic tissue . in this paper 
 , we described a case arising from the transverse mesocolon without heterotopic pancreatic tissue in an 18-year - old girl . 
1. Introduction
2. Case Report
3. Discussion
4. Conclusion