Revision 2: an immunohistochemical approach and evaluation of solid pseudopapillary tumour of the pancreas

Abstract

Solid pseudopapillary tumours (SPT) of the pancreas are uncommon, but with widespread and increased imaging, several of these lesions are coming to light incidentally and are subject to needle biopsies. On limited material and especially the solid or clear cell, variants of SPT can morphologically mimic most notably pancreatic neuroendocrine tumours and even metastatic renal cell carcinoma or melanoma. In this context, immunohistochemistry is important and useful in helping to reach the correct diagnosis. Several antibodies have been used in the immunohistochemical evaluation of SPT. As with most tumours, no one marker is specific, but rather a core panel is advocated. Recently, both b-catenin and Ecadherin have been shown to be of value in SPT. Nuclear and cytoplasmic decoration of tumour cells by b-catenin is seen in almost 100% of cases. This protein relocalisation away from the cell membrane is underscored by mutations of the b-catenin gene. Mutations of the CDH1 gene are very uncommon in SPT, but the immunohistochemically detected changes to the protein are consistent and present in 100% of cases. Using an Ecadherin antibody to the extracellular domain of the molecule results in complete membrane loss, while the antibody directed to the cytoplasmic fragment produces distinct nuclear staining of the tumour cells. In addition, there is concordance of staining abnormalities between the two antibodies. When combined with CD10 and progesterone receptor positivity, a diagnosis of SPT can be rendered with confidence even in small biopsy samples.With the advent of sophisticated, high-resolution non-invasive imaging techniques, the detection of incidental small lesions throughout the body is increasing. Imaging of the pancreas has kept pace with this growing trend, resulting in smaller lesions being detected and investigated. So-called incidental pancreatic cystic lesions are being increasingly documented, and a recent publication quotes an incidence of 0.2-0.7%.1 Although techniques such as multidetector computed tomography and magnetic resonance pancreatography allow for detailed visualisation and characterisation of pancreatic cysts, pathological and/or cytological evaluation remains the gold standard when it comes to reaching a definitive diagnosis. In concert with this, more image-directed needle biopsies are being sent for pathological evaluation. Inherent in this are the pitfalls of sample size and representativity, two factors that add to diagnostic difficulty even in the best of circumstances. With limited material the pathologist tends to be more dependent on ancillary techniques to confirm a morphological opinion, and immunohistochemistry is still the bedrock, routine investigation that is resorted to. Besides pancreatic pseudocysts, other intrinsic cystic lesions of the pancreas that are important are: serous cystic neoplasms, mucinous cystic neoplasms, intraductal papillary mucinous neoplasm and solid pseudopapillary tumours (SPT). 2SPT is an uncommon primary pancreatic tumour, constituting 1-2%...

Frantz’s tumor in a female patient with diarrhea: case report of a rare pancreatic neoplasm

“…Other markers suggestive of pseudopapillary solid tumor of the pancreas are vimentin, beta-catenin and progesterone. Alpha-1-antitrypsin and alpha-1-antiquimiotrypsin support pancreatic exocrine origin, while neurospecific enolase and synaptophysin are characteristic of neuroendocrine tumor 14,15 . In presented case, abdominal CT was sufficient to evaluate the tumor resectability.…”

Limited usefulness of histopathological features in identification of a clinically aggressive solid-pseudopapillary neoplasm of the pancreas

“…The immunohistochemical profile of SPN is relatively specific [24]. SPN usually express β-catenin (nuclear stain), CD10, CD56, and PgR [24].…”

“…IHC stains useful in diagnosis of SPN (β-catenin, CD10, CD56, progesterone receptor (PgR), synaptophysin, p53, Ki-67, claudin-5) were performed [22,[24][25][26]. Details on IHC protocols are described in Supplementary Table I.…”

“…Some nuclear morphometric features may also be useful for prediction of clinical aggressiveness of SPN as well [69]. Some researchers tested IHC stains as potential predictors of aggressive behavior: CD10, CD56, PgR, synaptophysin, p53, Ki-67, α1-antitrypsin, α1-antichymotrypsin, neuron-specific enolase, galectin-3, vimentin, chromogranin, pan-cytokeratin, Cam5.2, and epithelial membrane antigen (EMA) [11,24,32,33,70,71].…”

Solid pseudopapillary neoplasm of the pancreas mimicking a pseudocyst of pancreas

“…Other positive markers include alpha-1-antitrypsin and alpha-1-antichymotrypsin, synaptophysin and Pan CK in 70e75%, Vimentin in 60% and negative for Chromogranin A. 9,10 The fundamental differential diagnosis includes nonneoplastic lesions like inflammatory pseudocyst, and neoplastic exocrine and endocrine tumours like, mucinous cystic tumour, serous microcystic tumour, cystadenocarcinoma, acinar cell carcinoma, pancreatoblastoma and non-functioning pancreatic islet cell tumour.…”