P Van Eyken

On the existence and location of cardiac mucosa: an autopsy study in embryos, fetuses, and infants

Background: The incidence of gastric cardiac adenocarcinoma has increased in the last decades. Gaining insight into the pathogenesis of this lesion is hampered by the limited knowledge of the origin and histology of cardiac mucosa (CM). Currently, the location, extent, and even the existence of CM are controversial. Aims: We studied the development of the gastro-oesophageal junction (GOJ) in embryos, fetuses, and infants to clarify if CM is a normal structure at birth and where it is located. Subjects: Twenty one autopsy cases were evaluated ranging in age from 13 weeks’ gestational age (GA) to seven months. Methods: The distal oesophagus and proximal part of the stomach were embedded entirely. Serial sections were stained with haematoxylin-eosin and alcian blue/periodic acid-Schiff. The following parameters were measured: length of abdominal oesophagus; length of columnar lined oesophagus; length of CM; and distance from CM to angle of His. Results: CM was present in all evaluated sections. Its mean length varied throughout gestation. A maximum value was reached at a GA of 16 weeks (1.2 mm). After term delivery it was very short (0.3–0.6 mm). CM was proximal to, or straddled, the angle of His in all cases. During gestation, the mucin staining pattern of the CM was to a high degree similar to that of the developing pyloric mucosa. Conclusions: CM develops during pregnancy and is present at birth as a normal structure. If the angle of His is taken as a landmark for the GOJ, CM is located in the distal oesophagus.

The diagnosis of dysplasia and malignancy in Barrett's oesophagus.

Barretts metaplasia is associated with an increased risk for adenocarcinoma. Adenocarcinoma develops through a multistep process characterized by defects in genes and morphological abnormalities. The early morphological changes of the process are called ‘dysplasia’. Dysplasia is defined as an unequivocal neoplastic (premalignant) transformation confined within the basement membrane. For most Western pathologists malignancy is defined as invasion and characterized by a breach through the basement membrane. Japanese pathologists rely on cytological atypia and complex branching of crypts. Cytological and architectural abnormalities allow identification of dysplasia on routinely stained sections. A distinction is made between low‐ and high‐grade dysplasia. The differential diagnosis between low‐grade dysplasia and reactive changes can be difficult. Therefore a second opinion is strongly recommended, not only for high‐grade dysplasia but also for low‐grade. Immunohistochemistry for p53 and flow cytometry for detection of aneuploidy can support the diagnosis. Identification of dysplasia and malignancy depends on the number of biopsy samples examined. The minimum number of biopsies required has not yet been determined and depends partly on the length of the metaplastic segment. It has been proposed to sample with four quadrant biopsies at 20‐mm intervals. New endoscopic techniques can increase the diagnostic yield. Endoscopically visible lesions increase the risk of finding malignancy. The time sequence for the progression of dysplasia is not known but progression from low‐ to high‐grade and cancer has been shown to occur over a period of years although it may not be inevitable.

Epithelioid granulomas, pattern recognition receptors, and phenotypes of Crohn’s disease

Introduction: Crohn’s disease is a chronic inflammatory disorder of the gut. It is assumed that a defective interaction between the bacterial flora of the gut and the innate immune system plays a key role in the pathogenesis of the disease. This may lead to specific histological lesions. The epithelioid granuloma is particularly interesting in this regard as it is also observed in several bacterial infections of the gut. Aims and methods: We hypothesised that genetic or environmental factors with a known influence on inflammation or immunity would lead to an increased prevalence of granulomas. Therefore, surgical specimens from 161 patients were evaluated for the presence of granulomas. Patients were genotyped for the three single nucleotide polymorphisms in caspase recruitment domain 15 (CARD15)/NOD2 associated with CD and for Asp299Gly in Toll-like receptor 4 (TLR4). Results: The overall prevalence of granulomas was 68.9%. We did not find a significant correlation between granulomas and TLR4 or CARD15 variants. The frequency of granulomas increased with more distal disease (63% small bowel, 72% right colon, 88% left colon, 90% rectum; p = 0.01). Granulomas were more frequent in younger patients (odds ratio 0.95 (95% confidence interval 0.92–0.98) p = 0.007). Conclusion: In this study of 161 well documented CD patients, we found no significant association between CARD15 and TLR4 variants and granulomas. This finding seems to refute our initial hypothesis. However, it may be that additional factors are needed for granuloma development. Granulomas may develop only when specific bacterial components are present. Therefore, future research on granuloma pathogenesis should be orientated towards detection and identification of bacterial components in these lesions.

Value of histochemical stains for copper in the diagnosis of Wilson's disease

Aims: The histochemical demonstration of hepatic copper is important in the diagnosis of Wilsons disease (WD). Conflicting results have been published with regard to the ability of different histochemical methods to demonstrate copper storage in the liver. Therefore, we evaluated the diagnostic value of three available histochemical methods in a large series of patients affected by WD.

Abundant expression of cytokeratin 7 in fibrolamellar carcinoma of the liver

Two cases of fibrolamellar carcinoma of the liver, one with lymph node metastasis are reported. Using immunohistochemistry as well as one‐ and two‐dimensional gel electrophoresis and Western blotting, tumour cells of both primary lesions and of the metastasis were found to express cytokeratin polypeptides 8 and 18 and, surprisingly, cytokeratin 7. A small number of cells also expressed cytokeratin 19. This is the first detailed analysis of the cytokeratin expression of fibrolamellar carcinoma, and is also the first to present biochemical evidence that, contrary to what has been suggested, hepatocellular carcinomas do not always preserve the pattern of cytokeratin expression of normal hepatocytes.

Transferrin receptor expression in human hepatocellular carcinoma: An immunohistochemical study of 34 cases

Using a panel of five monoclonal anti‐transferrin receptor antibodies, we investigated the transferrin receptor expression in 34 human hepatocellular carcinomas of Belgian (n=6), Italian (n=7) and South African (n=21) origin. For comparison the tumours were also stained with the monoclonal antibody BK 19.9, recognizing an antigen biochemically similar to the transferrin receptor, and with a monoclonal antibody against the epidermal growth factor receptor. Hepatocellular carcinomas express large amounts of transferrin receptors as demonstrated by the intense transferrin receptor immunostaining in 33/34 cases. Differences in staining pattern between and within the tumours were not related to the degree of tumour differentiation, nor to the origin or race of the patient. In 15 cases which included non‐tumoural tissue, the tumour was more intensely stained than the surrounding liver parenchyma. The BK 19.9 immunoreactivity was generally weaker and mainly involved stromal cells, except in three cases where an intense staining of the tumour cells was seen. The epidermal growth factor receptor staining was also weaker and only in four cases was the immunoreactivity of the tumour stronger than the surrounding parenchyma. Demonstration of the transferrin receptor may be useful for the detection of malignant foci in liver biopsies. This may be of particular interest in the histological investigation of minute hepatocellular carcinomas.

Efficacy of interferon alfa-2b with or without prednisone withdrawal in the treatment of chronic viral hepatitis B. A prospective double-blind Belgian-Dutch study

A prospective, double-blind study was carried out to assess the efficacy of interferon alfa-2b, with or without pre-treatment prednisone withdrawal, in patients with chronic hepatitis B. A total of 57 Belgian and Dutch patients were included in the study. Patients were divided into four treatment groups: Group A, prednisone withdrawal followed by interferon 5 million units per day; Groups B and C, placebo followed by interferon 5 or 1 million units, respectively; and Group D, untreated controls followed for 1 year. All treated patients received interferon for 16 weeks. Two of the 14 control patients lost hepatitis B e antigen during the year of study, and only one of 15 patients in the interferon 1 million units group. Among the 28 patients receiving 5 million units of interferon (with or without prednisone withdrawal), ten (36%) cleared hepatitis B e antigen during the study or within 6 months of the end of therapy. This was associated with a marked improvement in serum transaminase levels. When comparing Groups A and B, it was found that prednisone withdrawal therapy enhanced the response to interferon in patients with pre-treatment serum alanine aminotransferase levels below 100 IU/l, bringing the seroconversion rate up to 50%, compared to 17% on interferon alone. This effect was not seen in patients with high pre-treatment transaminase levels. All treatment responders showed a marked improvement in Knodell index score, whereas in the 15 non-responders from groups A and B, overall inflammatory activity remained the same in six, improved in five and worsened in four.(ABSTRACT TRUNCATED AT 250 WORDS)

Validation of 16S rDNA sequencing in microdissected bowel biopsies from Crohn's disease patients to assess bacterial flora diversity

The bowel flora is implicated in Crohns disease (CD) pathogenesis but its precise role is still unclear. Several non‐mutually exclusive hypotheses have been proposed: an unidentified persistent pathogen; excessive bacterial translocation; an immune system abnormality in response to normal bacteria; or a breakdown in the balance between protective and harmful bacteria. These hypotheses can be tested by identifying bacteria in specific microscopic bowel structures or lesions. The present paper describes a novel technique to assess bacterial flora diversity in bowel biopsies, by combining laser capture microdissection with broad‐range 16S rDNA sequencing. Fifty‐four samples comprising histologically normal and pathological mucosa, MALT, ulcers, submucosal lymphangiectasias, epithelioid granulomas, and lymph nodes were microdissected out of 30 bowel biopsies from five CD patients. Bacterial 16S rDNA was successfully amplified by PCR in all samples, and PCR products from 15 samples were selected for cloning and sequence analysis. A total of 729 bacterial DNA sequences were analysed, which could be attributed to six different phyla (Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Fusobacteria, and Planctomycetes). DNA from typical bowel bacteria (Enterobacteriaceae, Clostridiales, Bacteroidetes, Fusobacteria) was detected in all microdissected areas. It was thus convincingly demonstrated that 16S rDNA sequencing can be combined with microdissection to study the bowel flora. However, no specific persistent pathogen causal for CD was identified. The results suggest that Enterobacteriaceae may initiate or colonize ulcers in CD. Translocation of bacteria through established mucosal lesions or as a result of increased permeability may be involved in the evolution towards chronic inflammation and in the establishment of persistent lesions. Further study is needed to confirm these preliminary findings. Copyright

Review article: the nature of oesophageal injury in gastro-oesophageal reflux disease

The purpose of this review was to explore issues relating to the nature of oesophageal injury in gastro‐oesophageal reflux disease. Several structural and functional elements of the oesophageal epithelium provide for an inherent resistance against refluxed material. It is only when this defence is overcome that reflux‐induced damage ensues.

Transferrin receptor expression in benign tumours and in hepatoblastoma of the liver

To further investigate the possible usefulness of antitransferrin receptor staining in the differential diagnosis between benign and malignant primary liver tumours, we examined the transferrin receptor expression in ten cases of focal nodular hyperplasia, six of nodular regenerative hyperplasia, two adenomas and six hepatoblastomas. In focal nodular hyperplasia, the ductular structures were always positive and the parenchymal cells displayed three staining patterns of moderate intensity. In nodular regenerative hyperplasia there was scattered, relatively weak transferrin receptor staining. The tumour cells in the adenomas were only weakly positive. Three hepatoblastomas showed an intense staining of tumour cells; one was weakly positive and two were negative. A high intensity of transferrin receptor staining, as previously described in hepatocellular carcinomas, was only observed in the hepatoblastomas. This gives further credence to the usefulness of strong transferrin receptor expression in evaluating the malignant nature of tumour foci in liver biopsies.