Paneth cell-rich flat adenoma of the rectum: report of a case

Gastroesophageal junction Paneth cell carcinoma with extensive cystic and secretory features - case report and literature review

Background

Carcinomas composed predominantly or purely of malignant Paneth cells were rarely reported in gastrointestinal system. They have not been reported at gastroesophageal junction nor has the association with Barrett esophagus been explored. None of the previous studies has mentioned any peculiar histologic features other than typical adenocarcinoma containing neoplastic Paneth cells. The Her2/neu status and the expression of beta-catenin in Paneth cell carcinoma at gastroesophageal junction have not been studied although the activated beta-catenin pathway was recently demonstrated in neoplastic Paneth cells in colon.

Case presentation

A 70-year-old Caucasian male who initially presented in the emergency room due to upper gastrointestinal bleeding was subsequently found to have a submucosal nodule at gastroesophageal junction. A diagnosis of adenocarcinoma was rendered on biopsy. Histologic examination of the subsequent endoscopic mucosal resection revealed an adenocarcinoma with various levels of differentiation which are zonally distributed. The deeper portion of the tumor showed well-differentiated bland-appearing glands with extensive cystic and secretory changes. The cytoplasm of tumor cells and secretion demonstrated marked reactivity with lysozyme antibody on immunohistochemical stain. The tumor had a peculiar Her2/neu staining pattern with cytoplasmic and nuclear stain in poorly-differentiated area and no stain in well-differentiated area. Only membranous stain was detected with beta-catenin antibody.

Conclusion

We reported the first case of Paneth cell carcinoma at gastroesophageal junction. The tumor had well-differentiated area which, when sampled in small biopsies, can mimic benign lesions including those related to proton pump inhibitor therapy. Lysozyme immunohistochemical stain may be helpful when difficulty in diagnosis arises. Her-2/neu was negative but showed a distinct staining pattern. In contrast to neoplastic Paneth cells in colon, beta-catenin pathway did not seem to be activated. More studies are needed for the etiology, pathogenesis, clinical course, prognosis and treatment of Paneth cell carcinoma.

The unique pathology of nonpolypoid colorectal neoplasia in IBD

Patients with inflammatory bowel disease may develop dysplasia in the cryptal epithelium, polypoid neoplasias, and nonpolypoid (flat) adenomas, lesions at risk to proceed to colorectal carcinoma. The onset of invasion in nonpolypoid adenomas may occur without changes in the shape or the size of the lesion. In experimental animals, some colonotropic carcinogens induce polypoid and nonpolypoid neoplasias and others induce polypoid neoplasias exclusively. Some of the biologic attributes of nonpolypoid adenomas in humans can be demonstrated in laboratory animals.

Ultrastructural and histochemical study on the Paneth cells in the rat ascending colon

Paneth cells (PCs) contribute to the host defense against indigenous bacteria in the small intestine. We found Paneth cell-like cells (PLCs) in the rat ascending colon, but the nature of PLCs is never clarified. Therefore, the present study aimed to clarify the cytological characteristics of PLCs and discuss their cellular differentiation. PLCs were localized in the bases of intestinal crypts, especially follicle-associated intestinal crypts in proximal colonic lymphoid tissue, but were very seldom found in the ordinary intestinal crypts of the ascending colon. PLCs possessed specific granules with highly electron-dense cores and haloes, as well as PCs in the small intestine. The secretory granules of PLCs were positive for PAS reaction, lysozyme and soluble phospholipase A2, but negative for Alcian blue staining, β-defensin-1 and -2, as well as the ones of PCs. Furthermore, intermediate cells possessing both the PLC-specific granules and the mucus granules similar to those of goblet cells (GCs) were occasionally found in the vicinity of PLCs. Intermediate cells ranged from goblet cell-like cells rich in mucus granules to PLC-like cells with few mucus granules. The cellular condensation and fragmentation were exclusively found in PLCs but never seen in intermediate cells or GCs. The PLCs, which were identified as PC, were suggested to be transformed from GCs through intermediate cells and finally to die by apoptosis in intestinal crypts of proximal colonic lymphoid tissue in the rat ascending colon.

Colonic crypt organization and tumorigenesis

An appreciation of colonic crypt organization has become essential to any understanding of tumorigenesis in the colon. Intestinal crypts house tissue-specific, multipotential stem cells, which are located in the niche at the base of the intestinal crypt and are capable of regenerating all intestinal cell types. Recent advances in our understanding of crypt biology, including how mutations in stem cells become fixed and expand within the epithelium, has led to new theories on the origins of colonic adenomas and cancers.

Expression of calnexin reflects paneth cell differentiation and function

It has been suggested that the behavior and function of Paneth cells in metaplasia are different from those found in normal intestinal mucosa. In this study, we investigated whether calnexin, a protein involved in secretory pathways, might be associated with differentiation and function of Paneth cells in normal small intestine, in complete intestinal metaplasia of the stomach, and in Paneth cell-rich adenomas. Differentiation and function of Paneth cells was monitored by Ki67, lysozyme, and morphologic features. Using a newly established monoclonal antibody, we found that calnexin is regularly synthesized by Paneth cells of normal small intestine. In these cells, the staining intensity of calnexin was inversely correlated with their content of secretory granules (lysozyme). In contrast, Paneth cells of intestinal metaplasia and Paneth cell-rich adenomas showed a reduced immunostaining of both calnexin and lysozyme. Moreover, these Paneth cells synthesized the proliferation marker Ki67, a phenomenon that was never observed in Paneth cells of normal small intestine. In vitro experiments using CaCo2 cells showed that the expression of calnexin is not directly affected by the induction of mitosis. In conclusion, calnexin probably reflects the status of Paneth cell differentiation and function. The results do not necessarily indicate that calnexin has a function in Paneth cell proliferation.

Multipotential stem cells in adult mouse gastric epithelium

Previous studies of chimeric animals demonstrate that multipotential stem cells play a role in the development of the gastric epithelium; however, despite much effort, it is not clear whether they persist into adulthood. Here, chemical mutagenesis was used to label random epithelial cells by loss of transgene function in adult hemizygous ROSA26 mice, a mouse strain expressing the transgene lacZ in all tissues. Many clones derived from such cells contained all the major epithelial cell types, thereby demonstrating existence of functional multipotential stem cells in adult mouse gastric epithelium. We also observed clones containing only a single mature cell type, indicating the presence of long-lived committed progenitors in the gastric epithelium. Similar results were obtained in duodenum and colon, showing that this mouse model is suitable for lineage tracing in all regions of the gastrointestinal tract and likely useful for cell lineage studies in other adult renewing tissues.

Characterization of metastatic intestinal adenocarcinoma with differentiation into multiple morphologic cell types in a Virginia opossum

A captively maintained mature male opossum (Didelphis virginiana) utilized in a research protocol was presented with clinical signs of chronic diarrhea and severe muscle wasting. At necropsy, there was multifocal mural gastric, intestinal, and urinary bladder thickening, concurrent bilateral hydroureter and hydronephrosis, and extensive fibrous abdominal adhesions. Histologic evaluation revealed intestinal adenocarcinoma with coelomic metastasis to the stomach and urinary bladder. The adenocarcinoma was evaluated using histochemistry and electron microscopy. Paneth, enteroendocrine, and goblet cell differentiation was documented in primary and metastatic sites. This unique presentation of intestinal adenocarcinoma has not previously been reported in the opossum or any other animals. Intestinal neoplasia with Paneth cell differentiation is extremely rare and has been reported in humans with familial adenomatous polyposis.

Clonal analysis of mouse intestinal epithelial progenitors

BACKGROUND & AIMS

Little is known about the cell lineages leading from stem cells to the various terminally differentiated cell types of the intestinal epithelium. In particular, the existence and characterization of intermediate progenitor types remain open issues, which are discussed in this study.

METHODS

Chemical mutagenesis was used to genetically mark random intestinal epithelial cells by somatic mutation of the Dlb-1 locus. Intact epithelium was isolated at various times thereafter, and the composition, size, and location of mutant clones were scored.

RESULTS & CONCLUSIONS

Analysis of clone dynamics showed short-lived (days) progenitors (C1, M1, and Mix) yielding one or two cell types and long-lived (months) mucous cell progenitors (M0), columnar cell progenitors (C0), and pluripotential stem cells (S) capable of giving rise to all epithelial cell types. Furthermore, study of clonal dispersion, during crypt branching morphogenesis or cell migration, shows that mutant progenitors usually partition into only one of the two daughter crypts and that cells are often widely dispersed in spite of the extensive intercellular junctions in the epithelium.

Expression of group II phospholipase A2 in Paneth cells of an adenoma of the rectum. A case report

A case of tubulovillous adenoma in the rectum of a 51-year-old man is presented. The tumour contained numerous Paneth cells which formed well-developed glands in the basal areas. Group II phospholipase A2 and lysozyme were found in the tumour cells by immunohistochemistry. mRNA of group II phospholipase A2 was localized in the tumour cells by in situ hybridization. It was concluded that a considerable part of this rare type of tumour consisted of Paneth cells which were capable of synthesizing group II phospholipase A2.

Gastric and intestinal mixed and solely intestinal types of intestinal metaplasia in the human stomach

To generate a novel understanding of intestinal metaplasia (IM) on the basis of cellular differentiation status, a total of 132 gastric surgical specimens were studied using gastric and small intestinal cell markers by mucin histochemical and immunohistochemical techniques. The cases were divided into two types: (i) gastric and intestinal (GI) mixed type; and (ii) solely intestinal (I) type, with the reference to the presence of gastric and/or intestinal cell markers. The GI mixed type was subdivided into six subtypes: (I) a subtype consisting of surface mucous (Su), pyloric gland (Py), intestinal absorptive (Ab), and goblet (Go) cells, but lacking Paneth (Pa) cells, GI(Pa-); (ii) a GI(Pa-) subtype without Py cells, GI(Py-, Pa-); (iii) a GI(Pa-) subtype without Su cells, GI(Su-, Pa-); (iv) a GI(Su-, Pa-) subtype with Pa cells, GI(Su-, Pa+); (v) a GI(Pa-) subtype with Pa cells, GI(Pa+); and (vi) a GI(Pa+) subtype without Py cells, GI(Py-, Pa+). The I type was subdivided into: (i) a subtype consisting of cells with Ab and Go cells, I(Pa-); and (ii) a I(Pa-) subtype with Paneth cells, I(Pa+). The GI mixed subtypes, except for the GI(Py-, Pa-) and GI(Py-, Pa+), were characterized by intestinalized gastric pits connected with underlying pyloric glands. Immunohistochemical staining of proliferating cell nuclear antigen (PCNA) revealed a common proliferative cell zone between the two. The GI mixed type, especially the GI(Pa-) subtype, predominated in the pyloric mucosa, while the I type was most frequent in the fundic region, suggesting that the pathogenesis of IM differs between these two locations. The results of the study confirm that IM is an abnormal and unstable differentiation status between the stomach and small intestine.

Histologic classification of endoscopically removed flat colorectal polyps: a multicentric study

A total of 594 flat colorectal polyps, removed at endoscopy, were histologically classified into non-neoplastic (n = 49) and neoplastic (n = 545) polyps. Non-neoplastic polyps were subdivided into metaplastic (n = 45) and hyperplastic (n = 4), whereas neoplastic polyps were subdivided into adenomas (n = 481), intramucosal carcinomas (n = 28) and invasive adenocarcinomas (n = 36). Several adenoma phenotypes were discerned: tubular (n = 375), serrated (n = 59), villous (n = 39), mixed (n = 7) and fenestrated (n = 1). Intramucosal carcinomas were subdivided into tubular (n = 26) and serrated (n = 2), and invasive adenocarcinomas into tubular (n = 32), serrated (n = 3) and fenestrated (n = 1). The microscopic characteristics of each histologic phenotype described in this communication are defined and illustrated.