PanNET : Microscopic
Microscopic Features of Pancreatic Neuroendocrine Tumors (PanNET) (continued): Both functioning and non-functioning PanNETs display a variety of architectural patterns, including solid nests, trabecular, gyriform, rosettes, and glandular/ductular patterns. Multiple patterns are frequently seen within a single tumor. The stromal component in PanNETs ranges from delicate vascular channels between compact nests and strands of tumor cells to broad bands of densely hyalinized stroma widely separating tumor cell clusters. Stromal calcifications and psammoma bodies may be present (especially in somatostatinomas). Some PanNETs (especially insulinomas) contain stromal amyloid deposits composed of islet amyloid polypeptide (IAPP) which can be detected with immunostains. About this image: Well-differentiated PanNET showing uniform tumor cells in anastomosing cords and trabeculae as well as tubular/glandular structures.