Type 1 NETs are generally low-grade tumors with trabecular or solid architecture; immunohistochemistry demonstrates chromogranin
A, synaptophysin, and usually serotonin and somatostatin positivity (Figure 1, A and B).
SNEC showed strong reactivity with epithelial and neuroendocrine markers whereas ENB demonstrated immunoreactivity to synaptophysin and chromogranin
strongly, with weak to negative expression of epithelial markers.
Quantification of chromogranin
A may be useful in confirming the diagnosis of a pancreatic NET and assessing for persistent, recurrent, or metastatic disease.
In September 2001, the patient's serum serotonin and pancreatic polypeptide levels had risen even higher (1,386 ng/ml and 471 pg/ml, respectively), and his serum chromogranin
A had more than tripled to 970 ng/ml (figure 4).
103-110) [beta]-catenin, E-cadherin, CD10, vimentin, and chromogranin
are the most effective IHC panel for confirming the diagnosis of SPT.
Therefore, in such cases we begin with a broad spectrum of antibodies depending on the clinical and morphologic findings, often including pancytokeratin, p63, CK903/34[beta]E12, GATA3, PSA, prostate-specific membrane antigen, CD45, CD20, CD3, chromogranin
, and synaptophysin.
Neurone-specific enolase, chromogranin
, CD56, immunoperoxidase, synaptophysin, epithelial membrane antigen, calcitonin, and bombesin stains may be useful to establish the diagnosis.
The most sensitive and specific immunohistochemical markers are synaptophysin and chromogranin
Immunohisto-chemically solid pseudopapillary tumor of pancreas can show overlapping expression of pan CK, synaptophysin, CD56, chromogranin
, CD10 and vimentin with neuroendocrine tumors19,20, the expression of neuroendocrine markers with pancreatoblastoma and pancreatic enzymes with acinar cell carcinoma18.
The most studied chromogranin
is CgA, which was first isolated from chromaffin cells of the adrenal medulla as a single polypeptide chain of 439 amino acids and 10 dibasic cleavage sites.
Detection of parathyroid hormone (PTH) and chromogranin
are strongly associated with parathyroid cell origin, while detection of thyroglobulin is strongly associated with thyroid follicular cell origin.
Immunohistochemistry studies using chromogranin
and Ki67 markers confirmed the diagnosis.