Insulinoma : Microscopic Features
Insulinoma - Microscopic Features: There are no histologic differences between functioning and non-functioning pancreatic neuroendocrine tumors (PanNETs). Like non-functioning PanNETs, insulinomas also display a variety of architectural patterns, including trabecular, tubulo-acinar and solid growth patterns. The anastomosing trabeculae are frequently separated by bands of hyalinized stroma. Stromal deposits of amyloid composed of islet amyloid polypeptide are seen in 5% of insulinomas (shown in this image). They are not specific for insulinomas and may also be present in other PanNETs. The cellular features of insulinomas are identical to those of other PanNETs. The neoplastic cells are small, monomorphic, cuboidal with finely granular eosinophilic or amphophilic cytoplasm. The nuclei are centrally located, uniform, and round to oval with coarsely clumped chromatin (salt and pepper appearance).