The patient underwent the Whipple procedure, and histopathology evaluation confirmed:

The section reveals tissue fragments, including the pancreas, small intestine with the duodenal ampullary region, lymph nodes and gallbladder. The subampullary area represents simple adenomatous proliferation. The pancreas tissue represents a neoplasm composed of an atypical proliferation of pleomorphic cells that are invasive, arranged in aggregates, in an organoid pattern, and in solid sheets. Intervening are scattered multinucleated tumor giant cells, the neoplasm shows occasional gland-like structures, lined by atypical cuboidal to columnar epithelial cells, despite cellular pleomorphism, mitosis is rare, necrosis absent. The tumor invaded peripancreatic fat and between smooth muscle bundles of the surrounding gastrointestinal wall. 
IHC stains are positive for CD10, CD56, PR and B-cathenin and negative for NSE, SMA, EMA, and CD15.
All included lymph nodes showing reactive hyperplasia. 

Histopathology diagnosis:
Pancreatic carcinoma, anaplastic pleomorphic type with the neuroendocrine feature.