MICROSCOPIC DESCRIPTION: The smears and cell block section contain scattered groups and cords of atypical epithelial cells. These cells have enlarged round nuclei, granular chromatin, small nucleoli and moderate amounts of cytoplasm. No mitoses or necrosis is seen. The tumor cells are synaptophysin, chromogranin and CD56 positive. The Ki-67 index is about 2%. The features are those of neuroendocrine tumor (WHO grade 1).
DIAGNOSIS: Neuroendocrine tumor.
Most endocrine pancreatic tumors are functional, secreting an active hormone, e.g. gastrin, insulin, or a vasoactive intestinal polypeptide (VIP).
This patient had a non-functioning neuroendocrine tumor, which is far less common.
These tumors tend to be highly vascular on CTA; they may contain calcification and cysts.
Invasion of adjacent vascular structures is seen less commonly than in adenocarcinoma of the pancreas.