Abstract: |
Pancreatic colloid carcinoma, also known as mucinous non-cystic carcinoma or gelatinous carcinoma, is a carcinoma of ductal origin, characterized morphologically by well-circumscribed pools of mucin that contain detached floating epithelial elements. Its distinction from conventional ductal adenocarcinoma is important because beyond the morphological dissimilarities, there are molecular and biologic differences between colloid and ordinary ductal carcinoma of the pancreas. Clinically, patients with colloid carcinoma often present with abdominal/epigastric pain and diarrhoea. They usually have larger tumours than ordinary ductal adenocarcinoma at presentation. Often, an associated intraductal papillary mucinous neoplasm is found. Macroscopically, colloid carcinoma is frequently well demarcated and characterized by gelatinous appearance. Microscopic examination reveals well-delineated mucin pools that contain detached and scanty malignant epithelial cells. In contrast with the mixed carcinomas, which may focally exhibit a similar pattern, pure mucinous carcinomas (those in which most of the tumour is composed of colloid pattern) seem to have a more indolent course with longer survival rates than conventional adenocarcinoma. Even in the presence of lymph node metastases, the patients can sometimes attain prolonged survival. There are certain characteristics of colloid carcinoma that are being recognized increasingly as the potential reasons for its distinctive clinicopathologic attributes. One distinctive feature of colloid carcinoma cells is that they exhibit altered cell polarity in which the secretory activity of the cell is manifested at its stroma-facing surfaces. In addition, it seems that production of MUC2 type mucin, which is specific for colloid carcinoma or its precursors, might act as a barrier limiting the growth and spread of the tumor and partially explaining the indolent nature of these cancers. The frequent association of colloid carcinoma with intraductal papillary mucinous neoplasms and also the observation that they share a similar profile of MUC1 and MUC2 expression have suggested that these neoplasms may be characterized by a different carcinogenetic pathway than ordinary ductal adenocarcinoma, which is believed to originate from pancreatic intraepithelial neoplasia. © 2003 Elsevier Ltd. All rights reserved. |