Morphological lesions associated with human primary invasive nonendocrine pancreas cancer.

In 227 cases of human pancreas cancer (100 pancreatectomy specimens and 127 autopsies), pancreas duct epithelium not involved by invasive cancer was examined. Pancreas duct epithelium from 100 autopsies of patients with nonpancreatic cancer, matched by age and sex to the pancreas cancer autopsy cases, was used for control studies. The prevalence of squamous metaplasia, pyloric gland metaplasia, mucous hypertrophy, and focal epithelial hyperplasia was not greatly different in the two groups. Ductal papillary hyperplasia was three times more prevalent in pancrease cancer than in controls. Marked atypia occurred in 20%, and carcinoma in situ, in 18% of the pancreas cancer cases, but neither change was seen in the control cases. It is possible that focal epithelial hyperplasia was a precursor change but that it was overgrown by the cancer. Papillary hyperplasia could not be properly evaluated as a precursor lesion because of duct obstruction, but practically all cases of marked atypia and carcinoma in situ occurred in papillary lesions. Marked atypia and carcinoma in situ, by analogy to other cancers, would appear to be precursor lesions, and their presence in association with invasive cancer lends hope to the possibility that there is a significant, recognizable, in situ phase of the disease before invasive cancer occurs.