Histologic Variants : Cystic PanNET
Cystic Pancreatic Neuroendocrine Tumor (PanNET): Some PanNETs are predominantly cystic and have a unilocular cyst filled with serous fluid surrounded by neoplastic tissue in the cyst wall. They are well-differentiated with low mitotic activity and usually lack necrosis, perineural invasion, lymphovascular invasion or metastases. Cystic PanNETs are more often seen in MEN syndrome and more likely to harbor MEN1 mutations and less likely to have DAXX or ATRX mutations than their solid counterparts. These cases should be distinguished from PanNET arising within another type of cystic pancreatic neoplasm. Image courtesy of: Raul S. Gonzalez, MD; used with permission.