A mutated p53 suppressor gene has been found in 60 percent of cases and a mutant cKi ras gene in about 70 percent. Pancreatic carcinoma arises in the head twice as often as in the body and tail. Those in the head are detected earlier because of the appearance of obstructive jaundice. The neoplasms are firm to hard, grayish white masses grossly. Microscopically they vary from well differentiated to anaplastic adenocarcinoma.
Most tumors secrete mucin.
A dense fibrous stroma is common. Invasion of perineural spaces is frequently found and may account for the pain which may be severe. The neural invasion may extend into the extrapancreatic plexus. Malignant cells shed into the peritoneum which is second to the liver as a site of metastases. Regional lymph nodes and the lungs are also frequently involved.