Heterotopic pancreas of the stomach. Histogenesis and immunohistochemistry.

Ordinary histological investigation has suggested that heterotopic pancreas of the stomach may have two types of histogenesis; one is development from immigrated fetal pancreas tissue, and the other is development from primitive gastric mucosal epithelium following penetration into the submucosa with subsequent erroneous differentiation into pancreas tissue. It is suspected that type-I lesions include the majority of cases caused by immigration from fetal pancreas, and that some type-II cases arise through erroneous differentiation of primitive gastric mucosal epithelium. With regard to immunohistochemical findings, cells positive for pancreatic polypeptide and amylase were much more numerous in the acini of type-I cases compared with type-II cases. Positive cells were found not infrequently in the acini of type-II cases after staining for pancreatic polypeptide, insulin, glucagon, somatostatin, serotonin, and gastrin. On the other hand, a small number of cells in islets were not infrequently positive for alpha 1-antitrypsin, alpha 1-antichymotrypsin, and amylase. It is considered that in the heterotopic pancreas, ductal cells have the potential to differentiate into acinar cells and islet cells, as is the cases in the orthotopic pancreas.     

Histological study of heterotopic pancreas tissue of the stomach--histogenesis and immunohistochemical findings

Forty resected cases of heterotopic pancreas (15 of Heinrich's type I and 25 of type II) in the stomach were investigated. Acinic cells were more remarkably positive by pancreatic polypeptide and amylase in the cases of type I consisting of acinic cells, ducts and islet cells compared with those in type II consisting of acinic cells and ducts. Staining behavior by insulin, gastrin, glucagon, somatostatin and serotonin was similar to that of normal pancreas. However, the intestinal epithelium containing goblet cells and pyloric gland-like glands consisting of the cells with clear cytoplasm were not infrequently produced from the ducts in the lesions of type II. Muscle fibers with transition to muscularis mucosae were more frequently intermingled in the lesions of type II compared with type I. Acinic cell-differentiation in the mucosa apart from the main lesion was found in several cases of type II. It was suspected that there are two types of histogenesis for the heterotopic pancreas in the stomach; one arises from the fetal immigration of pancreas tissue in the stomach and the other from the immature gastric mucosal penetration into the submucosa with secondary differentiation to the pancreas tissue.     

人胎胰腺GnRH免疫反应细胞

目的：探讨促性腺激素释的激素(GnRH)免疫反应细胞在人胎胰腺的存在部位和数量变化。方法：用免疫组织化学SABC法，对37例第10-32w人胎胰腺内的GnRH-IR细胞进行观察，并用体视方法分析其数量变化。结果：人胎胰腺GnRH-IR细胞出现于第13w，其数密度随胎龄增加而增大；分布于胰岛及外分泌部的腺泡上皮、导管上皮细胞间。位于胰岛的GnRH-IR细胞呈圆形、卵圆形或多边形。位于腺泡上皮细胞间的GnRH-IR细胞多为锥体形，外分泌部的GnRH-IR细胞均为开放型细胞。结论：胰腺GnRH-IR细胞于胚胎第13w出现，广泛存在于内、外分泌部，其数量随胎龄增加而增加。     

Intraductal papillary mucinous adenoma that arises from pancreatic heterotopia within a meckel diverticulum

Neoplasia is an unusual complication of Meckel diverticulum. Most tumors of Meckel diverticulum are neuroendocrine or mesenchymal in origin. Adenocarcinomas represent a minority of the tumors that arise in Meckel diverticulum and are generally thought to develop from either endogenous small intestinal epithelium or heterotopic gastric epithelium. Despite the presence of ectopic pancreas in a small fraction of Meckel diverticula, convincing evidence of tumors that arise from heterotopic pancreatic exocrine tissue has not been described in this setting. Intraductal papillary mucinous neoplasms are relatively uncommon tumors of pancreatic ductal epithelial cells that line the main pancreatic duct or its major side branches. We present an unusual case of an intraductal papillary mucinous neoplasm that arose in a heterotopic pancreas within a Meckel diverticulum.     

Two distinct types of islet abnormalities associated with endocrine pancreatic tumours

Summary Morphological and immunocytochemical studies of pancreatic material from eighteen patients with endocrine pancreatic tumours revealed two distinct types of islet abnormalities, both of which were associated with neoformation of endocrine cells from duct epithelium. Due to this phenomenon and the occurrence of greatly increased numbers of certain endocrine cell types the abnormalities were tentatively classified as hyperplasias. Hyperplasia type I was characterized by increases in number of all islet cell types. Increments in numbers of insulin and glucagon cells were most important quantitatively. Neoformation of islet cells from ducts (nesidioblastosis) was especially conspicuous with this type of hyperplasia. To some extent the islet cell neoformation resembled that seen in the human fetal pancreas. Hyperplasia type I was found in addition in two patients having hypergastrinemia due to achlorhydria. It is suggested that this type of abnormality results from a stimulatory effect of gastrin on the formation of pancreatic islet cells. Endocrine pancreatic tumours other than Zollinger-Ellison tumours were frequently, but not invariably, associated with hyperplasia type II, characterized by striking increases in frequency (and conceivably total mass) of pancreatic polypeptide (PP) cells. The variable occurrence of hyperplasia type II could not be related to any specific clinical abnormality. It seems possible that this hyperplasia may represent a non-specific response to pancreatic injury.     

Immunohistochemical studies of endocrine cells in heterotopic pancreas

Summary Twenty-one specimens of heterotopic pancreas were investigated using the indirect immunoperoxidase method for insulin, somatostatin, glucagon, pancreatic polypeptide (PP) and gastrin. Ten specimens showed ducts, acini and islets, seven showed ducts and acini, and four showed a ductal component alone. Pyloric gland-like mucous glands were occasionally identified in association with the ductal component. In eight of ten lesions containing islets, the islets were round and had a clearly defined outline with many glucagon cells and either none or a modest number of PP cells (dorsal type). In the remaining two lesions, the islets showed varying sizes and irregular outline with many PP cells and a few or no glucagon cells (ventral type). In either type of islets, insulin and somatostatin were detected, but gastrin cells were absent. Some isolated endocrine cells were also present among the acinar and ductal components. Their occurrence in ducts was more frequent in lesions or areas mainly composed of the ductal compoment than in those with less prominent ductal tissue. In eight lesions a few gastrin cells were found in the ductal component which showed goblet cell metaplasia and pyloric gland metaplasia. An intimate relationship between goblet cell metaplasia and appearance of G cells is noteworthy.     

Primary gastric Ki-1 positive anaplastic large cell lymphoma: A report of two cases

Two cases with primary gastric Ki-1 positive anaplastic large cell lymphoma are presented. Morphologic features of both cases involved pleomorphism of the neoplastic cells, fibrosis and lymphatic infiltration. The neoplastic cells in both cases were positive for BerH₂ (CD30), LCA(CD45), lysozyme and alpha-1-antitrypsin (α₁-AT). In additional case, the neoplastic cells were additionally positive for MAC387 and (α₁,-antichymotrypsin (α,-ACT). The neoplastic cells in these cases were negative for L26(CD20), UCHL-1 (CD45RO), DAKO CD3 and epithelial membrane antigen (EMA). According to the results of the phenotypic studies, the authors consider that the neoplastic cells have some of the features of histiocytes.
Both patients at 2 and 8 years after surgery without chemotherapy are disease free. This lymphoma is well known to be frequently misdiagnosed as undifferentiated carcinoma. Although rare in occurrence, recognition of this primary lymphoma in the stomach has a significant clinical implication, as the authors consider that its prognosis might be better than undifferentiated carcinoma of the stomach.     

Immunohistochemical Investigation of Vimentin, Neuron-specific Enolase, α1-antichymotrypsin and α1-antitrypsin in Adenoid Cystic Carcinoma of the Salivary Gland

Fifty-four adenoid cystic carcinomas (ACC) arising in major and minor salivary glands as well as in normal salivary glands were studied by immunohistochemistry for the presence of vimentin, neuron specific enolase (NSE), α₁-antichymotrypsin (α₁-ACT) and α₁-_- antitrypsin (α₁-_- AT). Five patterns of histological differentiation were found in ACC, and for the cellular components of each, it was possible to establish a special immunohistochemical profile. In ACC, vimentin-positive cells were observed in the outer tubular, cyst-lining and small angular cells. NSE was positive in the myoepithelial cells of normal salivary gland. Neoplastic cells of ACC showed NSE positivity mainly in the small angular cells and partly in the duct luminal cells. α₁-ACT was localized in the intercalated duct cells and serous acinar cells of normal salivary gland, and in the duct luminal cells of ACC. α₁-AT could not be detected in any of the epithelial cells of normal salivary gland. In ACC, eosinophilic hyaline material in the cribriform spaces was positive for α₁-AT, but no positivity was demonstrated in tumor cells. The present study showed that there are at least two populations of tumor cells in ACC: duct luminal cells that express α₁-ACT, thus indicating their ductal character, and small angular cells that express vimentin, characteristic of non-luminal cells. Moreover, our results indicate that α₁-AT is a useful marker of basement membrane-like material.     

Gastric motility in soluble guanylate cyclase α1 knock-out mice

The principal target of the relaxant neurotransmitter nitric oxide (NO) is soluble guanylate cyclase (sGC). As the α₁β₁-isoform of sGC is the predominant one in the gastrointestinal tract, the aim of this study was to investigate the role of sGC in nitrergic regulation of gastric motility in male and female sGCα₁ knock-out (KO) mice. In circular gastric fundus muscle strips, functional responses and cGMP levels were determined in response to nitrergic and non-nitrergic stimuli. sGC subunit mRNA expression in fundus was measured by real-time RT-PCR; in vivo gastric emptying of a phenol red meal was determined. No changes were observed in sGC subunit mRNA levels between wild-type (WT) and KO tissues. Nitrergic relaxations induced by short trains of electrical field stimulation (EFS) were abolished, while those by long trains of EFS were reduced in KO strips; the latter responses were abolished by 1 H [1,2,4,]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). The relaxations evoked by exogenous NO and the NO-independent sGC activator BAY 41-2272 were reduced in KO strips but still sensitive to ODQ. Relaxations induced by vasoactive intestinal peptide (VIP) and 8-bromo-cGMP were not influenced. Basal cGMP levels were decreased in KO strips but NO, long train EFS and BAY 41-2272 still induced a moderate ODQ-sensitive increase in cGMP levels. Gastric emptying, measured at 15 and 60 min, was increased at 15 min in male KO mice. sGCα₁β₁ plays an important role in gastric nitrergic relaxation in vitro , but some degree of nitrergic relaxation can occur via sGCα₂β₁ activation in sGCα₁ KO mice, which contributes to the moderate in vivo consequence on gastric emptying.     

Expression of α5 (CD49e) and α6 (CD49f) Integrin Subunits on T Cells in the Circulation and the Lamina Propria of Normal and Inflammatory Bowel Disease Colonic Mucosa

Intestinal lamina propria T cells are believed to be derived, via the systemic circulation, from gut-associated lymphoid tissue. After migration into the lamina propria, T cells are capable of luminally directed migration following the loss of surface epithelial cells. For adhesion and migration within the extracellular matrix, T cells are likely to utilize the integrin family of adhesion molecules. The aim of this study was to quantitatively and qualitatively investigate the expression of α₅ and α₆ integrin subunits on the surface of human T cells that: (a) migrated out of the lamina propria, (b) remained resident within the matrix and (c) were present in the circulation. In both subpopulations of CD4 and CD8-positive T cells, from both normal and inflamed (inflammatory bowel disease) colonic mucosa, there were significantly fewer α₅ and α₆-positive cells than in the peripheral blood. In addition, there were significantly fewer α₆ integrin molecules on the surface of CD4 and CD8-positive lamina propria T-cell subpopulations, compared with those in the circulation. Our studies suggest that, following migration into the lamina propria, there is down-regulation of α₅ and α₆ integrin-subunit expression on the surface of T cells. Molecules other than members of very late activation antigen-5 (VLA-5) (α₅β₁) and VLA-6 (α₆β₁) families of adhesion molecules are likely to be important in interactions with extracellular components in the lamina propria of normal and inflamed human colonic mucosa.     

Carcinoma in jejunal pancreatic heterotopia.

BACKGROUND: Although heterotopic pancreas in the gastrointestinal tract is not uncommon, jejunal pancreatic heterotopia is a rare finding, and malignant transformation in such a location is very unusual. METHODS: We encountered a case of jejunal carcinoma in pancreatic heterotopia and because of its rarity, we reviewed the Armed Forces Institute of Pathology experience as well as the literature. The clinical, histopathologic, and immunohistochemical features were studied. RESULTS: In 109 patients diagnosed as having pancreatic heterotopia in the gastrointestinal tract between 1970 and 1997 at the Armed Forces Institute of Pathology, 67 cases (62%) occurred in the stomach, 42 (38%) in the small intestine, and none in the large intestine. We found 2 patients with adenocarcinoma arising in pancreatic heterotopia. The 2 cases arose in the jejunum. One was of the ductal type, while the other was an acinar cell carcinoma with focal ductular differentiation. In both cases the nontumoral pancreatic tissue contained ducts, acini, and islets. Review of the literature yielded 26 reports of 28 cases of carcinoma arising in heterotopic pancreas; of these, 18 were well documented. Only 1 occurred in the jejunum, and none was of the acinar type. CONCLUSIONS: Carcinoma in pancreatic heterotopia is rare, and acinar cell carcinoma in pancreatic heterotopia is extremely rare. Recognition of carcinoma in pancreatic heterotopia is important to prevent its misinterpretation as a metastatic tumor.     

Cystic lesion mimicking intraductal papillary mucinous tumor arising in heterotopic pancreas of the stomach and synchronous intraductal papillary mucinous adenocarcinoma of the pancreas

This article presents the study of a 66-year-old man with an asymptomatic pancreatic mass detected incidentally 4 months earlier. A magnetic resonance imaging scan revealed 2 distinct cystic masses in the pancreas and the gastric antrum. Microscopically, the pancreatic lesion showed dilated cysts containing papillary structures lined by mucinous epithelium, which showed a loss of polarity, an increased nucleus-to-cytoplasm ratio, a prominent nucleolus, and high proliferation on immunostaining for Ki-67. The gastric lesion was composed of heterotopic pancreatic tissue surrounding a large dilated cyst that was lined with mucinous epithelium and contained a few intraluminal papillae.     

Receptor for α1-Microglobulin on T Lymphocytes: Inhibition of Antigen-Induced Interleukin-2 Production

The human plasma protein α₁-microglobulin (α₁m) was found to inhibit the antigen-induced interleukin-2 (IL-2) production of two different mouse T-helper cell hybridomas. α₁m isolated from human plasma and recombinant α₁m isolated from baculovirus-infected insect cell cultures had similar inhibitory effects. Flow cytometric analysis showed a binding of plasma and recombinant α₁m to the T-cell hybridomas as well as to a human T-cell line. Radiolabelled plasma and recombinant α₁m bound to the T-cell hybridomas in a saturable manner and the binding could be eliminated by trypsination of the cells. The affinity constants for the cell binding were calculated to be 0.4–1 × 10⁵  M ⁻¹ using Scatchard plotting, and the number of binding sites per cell was estimated to be 5 × 10⁵–1 × 10⁶. The cell-surface proteins of one of the T-cell hybridomas were radiolabelled, the cells lysed and α₁m-binding proteins isolated by affinity chromatography. SDS–PAGE and autoradiography analysis of the eluate revealed major bands with M _r-values around 70, 35 and 15 kDa. The results thus suggest that α₁m binds to a specific receptor on T cells and that the binding leads to inhibition of antigen-stimulated IL-2 production by T-helper cells.     

Immunohistochemical Characterization of Human Cutaneous Mast Cells in Urticaria Pigmentosa (Cutaneous Mastocytosis)

To clarify the origin and function of human cutaneous mast cells (CMCs), immunohistochemical characterization was done in 19 cases of urticaria pigmentosa (cutaneous mastocytosis) using 9 antibodies (anti leukocyte common antigen, MX-PanB, anti lysozyme, anti α₁, antitrypsin, anti α₁-antichymotrypsin, anti vimentin, anti-neuron specific enolase, anti factor VIII related antigen, and anti-ACTH). CMCs showed positive reactions with anti α₁ anti-chymotrypsin and anti vimentin in almost all of the specimens. In more than half of the specimens, CMCs were stained positively with anti -α₁-antitrypsin, MX-PanB, and anti factor VIII related antigen. Anti-leukocyte common antigen and anti ACTH also showed positive reactions in some specimens. These results confirm the existence of vimentin filaments in CMCs and suggest a functional role of CMCs in hemostasis via factor VIII. Furthermore, immunohistochemical similarity between CMCs and granulocyte/macrophage group cells is also suggested.     

Immunosuppressive Properties of α1-Microglobulin

α₁-Microglobulin (α₁m), a serum glycoprotein (26,000 d). was found to impede the proliferative response of human lymphocytes to purified protein derivative (PPD) and tetanus toxoid. The data suggest that, α₁m operates through an unstable suppressor mechanism, which no longer can function after 24 h of preculturing. This effect of α₁m on antigen stimulation did not seem to be due to binding of α₁m to PPD or cells, to altered kinetics of the PPD response, or to non-specific cytotoxicity. In contrast, PPD-induced leucocyte migration inhibition was not reversed by α₁m. α₁m did not cause significant inhibition in experiments in which lymphocytes were stimulated by the mitogens phytohaemagglutinin or concanavalin A. Finally, α₁m had its own leucocyte migration inhibitory effect.     

Bombesin-induced desensitization of enzyme secretion in dispersed acini from guinea pig pancreas

Incubating dispersed acini from guinea pig pancreas with bombesin and then washing the cells to remove bombesin reduced the subsequent stimulation of amylase secretion caused by bombesin, litorin, or ranatensin by as much as 80%, but did not alter the stimulation of amylase secretion caused by cholecystokinin, carbamylcholine, A23187 or vasoactive intestinal peptide. This bombesin-induced desensitization was reversible, and the onset of the process, as well as its reversal, were time and temperature dependent. Neither desensitization or resensitization were inhibited by abolishing protein synthesis. The concentrations of bombesin required to cause desensitization were in the same range as those required to stimulate amylase secretion. Incubating pancreatic acini with vasoactive intestinal peptide did not reduce the subsequent stimulation of amylase secretion caused by vasoactive intestinal peptide, bombesin, or cholecystokinin. These results indicate that bombesin-induced desensitization of pancreatic acini reflects changes that occur at or close to the bombesin receptor.     

Gastric neuroendocrine carcinoma arising from heterotopic pancreatic tissue

An 85 year old man presented with symptoms of dyspepsia and increase in stool frequency of two months duration. Upper endoscopy revealed an ulcer and the biopsy was interpreted as carcinoma with endocrine features. A formal distal gastrectomy was planned, but intraoperatively, because of the patient's condition, a wedge resection was performed. Histology revealed a neuroendocrine tumour (grade 1), located mainly in the submucosa, which had caused mucosal attenuation and ulceration. Associated with the tumour and at its periphery was heterotopic pancreatic tissue composed of acini, ducts, and endocrine cells. The tumour was strongly positive for chromogranin and focally for synaptophysin. There was no associated chronic atrophic gastritis or G cell hyperplasia. A discrete focus of high grade neuroendocrine carcinoma (grade 3) within the typical (grade 1) neuroendocrine tumour was also present. This case illustrates a grade 1 neuroendocrine carcinoma, with a small grade 3 focus, arising within or intimately associated with heterotopic pancreatic tissue in the stomach. Although the two entities may be separate, their close topographical association favours the possibility of neuroendocrine carcinoma arising from the heterotopic pancreas. Pathologists should be aware of the occurrence of pancreatic heterotopia in the stomach and the association of carcinoma with it.     

α1-Microglobulin Glycopeptides Inhibit Antigen-Specific Stimulation of Human Peripheral Blood Leucocytes

Glycopeptides were prepared from proteolytically digested human and guinea pig α₁ microglobulin (α₁-m) by gel chromatography on Sephadex G-100 and affinity chromatography on concanavalin A-Sepharose. Amino acid analysis showed that the average glycopeptide was a tripeptide containing the amino acids aspartic acid/asparagine, isoleucine, and serine and/or threonine. It has earlier been shown that human α₁-m carries two or three N-glycosidically linked oligosaccharides of the high-mannose type. These preparations of glycopeptides inhibited the proliferative response of peripheral human blood leucocytes in the antigen purified protein derivative. The dose-response relationship of the inhibitions showed a greater specific activity of the glycopeptides than of whole α₁-m. Mild alkali treatment of human α₁-m did not affect its specific inhibitory activity, suggesting that the peptide backbone is of little importance for the immunosuppressive effect of α₁-m. No difference in inhibitory activity was seen between human and guinea pig native α₁-m or α₁-m glycopeptides. Human asialo α₁-m exerted a suppressive effect on the antigen-specific leucocyte proliferation similar to that of native α₁-m.     

Interaction and localization of Necl-5 and PDGF receptor beta at the leading edges of moving NIH3T3 cells: Implications for directional cell movement

It was previously shown that platelet-derived growth factor (PDGF) receptor physically and functionally interacts with integrin α_vβ₃, effectively inducing cell movement. We previously showed that Necl-5, originally identified as a poliovirus receptor, interacts with integrin α_vβ₃ and enhances its clustering and the formation of focal complexes at the leading edges of moving cells, resulting in an enhancement of cell movement. We showed here that Necl-5 additionally interacts with PDGF receptor in NIH3T3 cells and regulates the interaction between PDGF receptor and integrin α_vβ₃, effectively inducing directional cell movement. PDGF receptor co-localized with Necl-5 and integrin α_vβ₃ at peripheral ruffles over lamellipodia, which were formed at the leading edges of moving cells in response to PDGF, but not at the focal complexes under these ruffles, whereas Necl-5 and integrin α_vβ₃ co-localized at these focal complexes. The clustering of these three molecules at peripheral ruffles required the activation of integrin α_vβ₃ by vitronectin and the PDGF-induced activation of the small G protein Rac and subsequent re-organization of the actin cytoskeleton. These results indicate a key role of Necl-5 in directional cell movement by physically and functionally interacting with both integrin α_vβ₃ and PDGF receptor.