Extrapancreatic manifestations in autoimmune pancreatitis.

It is increasingly recognized that organs beyond the pancreas may be clinically involved in patients with autoimmune pancreatitis (AIP). Other gastrointestinal sites (such as the extrapancreatic biliary tree, liver, and ampulla) appear particularly affected, but involvement of many other organs (including kidneys, lungs, retroperitoneum, and brain) is increasingly reported. A similar histological lesion, characterized by an IgG4-positive lymphoplasmacytic infiltrate, affects both the pancreas and extrapancreatic tissues, strongly suggesting an aetiopathogenic link. In this review we discuss the clinical presentation and disease course, diagnostic features, and management of extrapancreatic involvement in AIP.

The development of duodenal microadenomas in FAP patients: the human correlate of the Min mouse.

UNLABELLED: The morphological changes associated with the adenoma-carcinoma sequence are well documented in the colorectum. Small intestinal carcinogenesis is thought to progress through a similar adenoma-to-carcinoma pathway, but there is a relative dearth of studies examining the associated morphological changes. The best-known mouse model of intestinal neoplasia, the multiple intestinal neoplasia (Min) mouse, has been criticized as a genetic model of intestinal neoplasia, as the majority of its tumours occur in the small intestine. We examined pancreatico-duodenal resection specimens from seven familial adenomatous polyposis (FAP) patients. Serial sections of these were stained with haematoxylin and eosin for beta-catenin and its downstream target CD44, for BMPR1a, lysozyme, carbonic anhydrase II, and with MIB-1. Individual dysplastic crypts were isolated and mutations in the FAP (APC) gene compared between the top and bottom of the crypt. We found that: (a) duodenal microadenomas are extremely common in FAP patients; (b) these grow in the core of duodenal villi, forming lesions similar to those described in the Min mouse; (c) many lesions arise as monocryptal adenomas and grow by a process of crypt fission and branching; (d) migrating adenomatous cells lose their dysplastic phenotype as they migrate up the crypt villous axis; and (e) Paneth cells lose positional information. IN CONCLUSION: (a) the morphological similarity of adenomas in the Min mouse and human suggest the Min mouse is a good model of FAP; (b) duodenal adenomas in FAP originate in monocryptal adenomas and follow the 'bottom-up' rather than the 'top-down' model of morphogenesis; (c) early microadenomas show evidence of cellular differentiation; (d) defects in the positioning of Paneth cells suggests disruption of the EphB2:EphB3 receptor system.