Solid pseudopapillary tumor

Kosmahl M, Seada LS, Janig U, et al. Solid-pseudopapillary tumor of the pancreas its origin revisited. Virchows Arch. 2000 436 473-480. 

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. 

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