Progress in the study of pancreatic cancer and its pathology.

Recent advances in diagnostic techniques allow detection of relatively small ductal cancers and mucinous cystic neoplasms of the human pancreas. The histopathological characteristics of a series of such small pancreatic carcinomas encountered in our hospital were: 1) all were invasive ductal carcinomas accompanied by fibrosis, 2) four of seven carcinomas were thought to originate in the branch ducts, 3) no precancerous lesions were found, and 4) lymph node metastasis was detected in only one patient. Mucinous cystic neoplasms were of two types: megacystic and ductectatic. The megacystic type is the classical mucinous cystic neoplasm. The ductectatic type is characterized by the presence of multilocular cysts (reminiscent of bronchiectasia of the lung), and papillary proliferation of the lining epithelium-differing from typical ductal carcinomas as well as from megacystic lesions in terms of morphological features, intrapancreatic location, patient age, and sex. The ductectatic type occurs exclusively in the head and body of the pancreas, and is found predominantly in aging males.