Small pancreatic tubular adenocarcinomas: clinicopathological analysis with immunohistochemical and histochemical evaluation.

Abstract

Ten cases of surgically resected small pancreatic tubular adenocarcinomas (PTA), grossly 2 cm or less were analyzed. Nine patients presented with symptoms. The cumulative 5 year survival rate was 14.8%. According to the criteria proposed by the Japanese Pancreatic Society, in three patients the PTA was stage I and in seven patients it was stage II. Immunohistochemical study detected overexpression of p53 in six PTA, of c-erbB-2 in four PTA, and of Ha-ras p21 in six PTA. the p53 overexpression was closely related to the poor clinical course (P < 0.05). All PTA focally had gastric mucin. In eight cases, mucous metaplasia was frequently found in the non-cancerous pancreatic tissues. Most of the mucous metaplastic cells had gastric mucin, and their staining patterns resembled those of the respective PTA. These findings support the putative hypothesis that most PTA arise from "gastric mucous cell metaplasia'. However, in two cases, mucous metaplasia was not found. In one other case, minute dysplastic glands determining the existence of in situ carcinoma or intrapancreatic metastasis were found in the islet of Langerhans, relatively distant from the main cancer. These findings also present the possibility that some PTA develop de novo without mucous metaplasia.