Three hundred and minety-one cases of primary pancreatic tumours, excluding endocrine tumours, were studied histologically. Carcinoma of the exocrine pancreas formned the largest group (98.5 per cent), benign tumours (1.25 per cent) and other malignant tumours (0.25 per cent) formed the remainder. Ductal adenocarcinoma was the commonest type and was divilded into four sub-types, papillary, well, moderately and poorly differentiated duct adeno-carcinoma. The moderately and poolrly differentiated tumours were the commonoest types. Papillary carcinoma was separated from the well differentiated tumours by its different morphological appearances and was found to exhibit different behaviour. Other special morphological types of pancreatic carcinoma, pleomorphic, mucinous, adenosquamous, acinar, microadenocarcinoma, cystadenocarcinoma and oncocytie carcinoma were also represented. Benign microcystadenomata (four cases) were considered because of their interesting morphological features and their singificance in the differential diagnosis of carcinoma. Based on the morphology and behaviour of these 391 tumours, the classification of panceratic carcinoma is discused and some rare types are compared with previously reported cases and discussed.

Primary pancreatic carcinomas were studied histologically and histochemically, to assess the frequency of dutal hyperplasia in tissue adjacent to malignat neoplams. Hyperplaaia waw divided into four types: simple, papillary, atypical and ductular, affecting large, medium and small ducts (ductules). All types of hyperplasia were frequently seen in areas adjacent to carcinomas, including ductal, pleomorphic, mucinous, adenosquamous, small and spindel cell and cystadenocarcinomas. In contrast, acinar cell carcinoma and microadenocarcinoma were less frequently associated with ductal hyperplasia. Mucin histochemistyr revealed differences in types of mucin betwwnd the normal ducts and hyperplastic pancreatic ducts and carcinomas. The former group comtained smal amouts of sulphated mucin while the latter showed a marked increase in neutral and sialomucins. Our study salso suggests that both papillary with the latter showed a marked increse in neutral and sialomucins. Our study salso suggests that both papillary and atypical hyperplasia are precancerous lesions, supporitng and hypothesis of ductal origin of pancreatic carcinomas. And atypical hyperplasia are prcancerous lesions, suporintg and hypothesis of ductal origin of poanereatic carcionmas.

The numbers of immunoreactive gastrin and somatostatin cells in gastric and duodenal mucosal biopsy specimens from dyspeptic patients with duodenal ulcers and dyspeptic controls without ulcers were calculated using a morphometric method. The levels of gastrin and somatiotatin in the tissue were also measured by the radioimmunssay. The results showed no significant difference in the number of G cells and the level of gaslrln in the tisse between the ulcer and nun-ulcer groups. However, the number of D ceils and the level of somaosutin in the tissue in ulcer patlems were remarkably reduced in comparison with those in non-ulcer patients (P<0.01 and P<0.05, respectively). The G: D cells and gastrin : somatostatin rsatios in ulcer patients were much higher than those in the non-ulcer control group It is considered that the reduction of D cells and the relative lack of somatostafin in duodenal ulcer patients might have a role in the mechanism of the duodenal ulceration.