Neoplasms of the pancreas are classified based on the cell type of origin, and can arise both from the exocrine (ductal epithelial, acinar, mesenchymal) and endocrine (islet) cells of the pancreas. Treatment of endocrine pancreatic neoplasms is reviewed in Chapter 42. Tumors arising from the exocrine pancreas are broadly classified as solid or cystic based on their gross appearance.
Solid Epithelial Tumors
It is of interest that although the pancreatic ductal epithelium comprises <10% of the pancreatic cell volume, ductal adenocarcinoma is by far the most common epithelial malignancy, accounting for at least 75% of all nonendocrine pancreatic malignancies. About 65% of ductal adenocarcinomas arise in the head of the pancreas, with 15% involving the body and tail, and 20% diffusely infiltrating the entire gland. Ductal adenocarcinoma of the pancreatic head frequently obstructs the intrapancreatic distal common bile duct, producing jaundice, and the main pancreatic duct, leading to a desmoplastic, fibrotic reaction and “obstructive chronic pancreatitis” (Figure 35.1). Ductal adenocarcinomas may invade locally into the duodenum, stomach, transverse colon, spleen, adrenal gland, or kidney. These malignancies also have a high frequency of microscopic infiltration into blood vessels, lymphatics, and the perineural sheath. Indeed, lymphovascular and perineural invasion have been shown to be independent prognostic factors of poor survival (2,3). At the time of resection, most ductal adenocarcinoma has invaded into local lymph nodes. As the disease progresses, distant metastases to the liver (80%), peritoneal cavity (60%), and lungs (50%) are common.
(A) Coronal computed tomography reconstruction demonstrating the relationship of a pancreatic head adenocarcinoma to the intrapancreatic bile duct (arrow); an endoscopically placed stent in the bile duct is white. Note the presence of pneumobilia in the right lobe of the liver. (B) Separate section of the patient depicted in (A) demonstrating dilated main pancreatic duct (arrow).
A large body of elegant experimental evidence has accumulated over the past decade suggesting that the development of pancreatic ductal adenocarcinoma follows a similar pattern to that observed in the colorectal adenoma ...
Get access to full content - subscribe to LWWOncology.com.