Solid-pseudopapillary neoplasm

Synaptophysin, also called protein p38, is a glycoprotein initially found in small vesicle membranes of neurons and of chromaffin cells in the adrenal medulla. It has been routinely used as a broad-spectrum marker in normal and neoplastic neuroendocrine cells including those of the pancreas however, strong synaptophysin immunoreactivity has been well-documented in tumors without any endocrine differentiation including solid-pseudopapillary neoplasm (SPN) of the pancreas, which is one of the most important differential diagnoses of endocrine neoplasia in this organ. 

The endocrine component shows immunoreactivity for chromogranin or synaptophysin > ° and, rarely, peptide hormones such as glucagon or somatostatin are expressed. In some cases of ACC, even the most typical acinar areas may show positivity with endocrine markers. Markers typically present in solid-pseudopapillary neoplasms (vimentin, CD56, and progesterone receptors) are negative. 

Immunohistogram of Solid-Pseudopapillary Neoplasm with Selected Antibodies... 

FIGURE 15.19 Solid-pseudopapillary neoplasm with diffuse cytoplasmic and nuclear fS-catenin labeling. 

Kim MJ, Jang SJ, Yu E. Loss of E-cadherin and cytoplasmic-nuclear expression of beta-catenin are the most useful immuno-profiles in the diagnosis of solid-pseudopapillary neoplasm of the pancreas. Hum Pathol. 2008 39 251-258. 

Tien YW, Ser KH, Hu RH, et al. Solid pseudopapillary neoplasms of the pancreas is there a pathologic basis for the observed gender differences in incidence Surgery. 2005 137 591-596. 

Gao D, Antonescu C, Wong G, et al. Positive immunohistochemical staining of KIT in solid-pseudopapillary neoplasms of the pancreas is not associated with KIT/PDGFRA mutations. Mod Pathol. 2006 19 1157-1163. 

Tanaka Y, Kato K, Notohara K, et al. Frequent beta-catenin mutation and cytoplasmic/nuclear accumulation in pancreatic solid-pseudopapillary neoplasm. Cancer Res. 2001 61 8401-8404. 

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