NCI: An infiltrating adenocarcinoma that arises from the epithelial cells of the pancreas. It affects males more often than females and the patients are usually over 50 years of age. Microscopically it is characterized by the presence of glandular (ductal) differentiation and desmoplastic stroma formation. Signs and symptoms include pain, loss of weight, and jaundice. It grows rapidly and is usually detected after it has metastasized to other anatomic sites. The prognosis is usually poor.