The occurrence of terminal ileal histological abnormalities in patients with coeliac disease.

INTRODUCTION: Coeliac disease causes histological changes throughout the small bowel, but is often a proximal lesion. We wanted to assess whether terminal ileal histological abnormalities occurred more commonly in patients with coeliac disease and if specific assessment of intraepithelial lymphocytes increases the recognition of undiagnosed coeliac disease. METHODS: Terminal ileal biopsies were prospectively examined over a 3-year period (April 2001-May 2004). Patients were included if they were found to have a synchronous duodenal biopsy that gave a new diagnosis of coeliac disease (n=20). Terminal ileal biopsies taken at colonoscopy during the same period were also examined from four groups of patients: coeliac disease established on a gluten-free diet but with persisting symptoms (n=25), inflammatory bowel disease (n=47), chronic diarrhoea (n=44) and polyp surveillance (n=47). All biopsies were graded according to the Marsh criteria and an intraepithelial lymphocytes count per 100 enterocytes was obtained. RESULTS: There was only one patient from all five groups who had villous atrophy of the terminal ileal. This patient had a new diagnosis of coeliac disease. The mean intraepithelial lymphocytes count in the coeliac disease group was 23.7 intraepithelial lymphocytes/100 enterocytes. This was significantly higher than the control groups: coeliac disease on a gluten-free diet=17.5 (p<0.012), inflammatory bowel disease=12.3 (p<0.0001), diarrhoea=12.6 (p<0.0001) and polyp=13.7 (p<0.0002). Validating terminal ileal villous intraepithelial lymphocytes counts as a test for coeliac disease using an intraepithelial lymphocytes/100 enterocytes of >25 gives a sensitivity of 45% and a specificity of 97.8%. CONCLUSION: Routinely quantifying terminal ileal intraepithelial lymphocytes may be of limited clinical value. However, subjective recognition of raised intraepithelial lymphocytes on a terminal ileal biopsy should alert the clinician to the possibility of coeliac disease.

Offline telepathology diagnosis of colorectal polyps: a study of interobserver agreement and comparison with glass slide diagnoses.

BACKGROUND/AIMS: Technological advances have produced telepathology systems with high quality colour images and reasonable transmission times. Most applications of telepathology have centred on the remote diagnosis of frozen sections or remote real time expert opinions. This study investigates the reproducibility and accuracy of offline telepathology as a primary diagnostic medium for routine histopathology specimens. METHODS: One hundred colorectal polyps (50 hyperplastic, 50 adenomatous) were presented in a randomised order to five histopathologists as offline images on a telepathology workstation. Six images of each case were used: the slide label, a low power scan of all material on the slide, and four higher magnification views. The times taken to prepare the images, and to make the diagnoses, were recorded. Interobserver agreement was measured with kappa statistics and compared with the glass slide diagnoses. RESULTS: The kappa statistics for the interobserver agreement on the telepathology images lay in the range of 0.90-1.00, which is interpreted as excellent agreement, and were significantly higher than those for the glass slide diagnoses (range, 0.84-0.98; p = 0.001). The median time taken to capture the images for a case was 210 seconds. The median time taken to make a diagnosis from the telepathology images was five seconds, which was significantly shorter than for the glass slide diagnoses (median, 13 seconds; p < 0.0005). CONCLUSIONS: Offline telepathology has the potential to be a primary diagnostic medium for routine histopathology with a high degree of reproducibility and short diagnosis times. Further studies are required to validate offline telepathology for different types of specimens and different operators of the image capture system.

What levels of agreement can be expected between histopathologists assigning cases to discrete nominal categories? A study of the diagnosis of hyperplastic and adenomatous colorectal polyps.

AIMS: To assess the levels of agreement between histopathologists for a two-class nominal categorization process--the discrimination between hyperplastic and adenomatous colorectal polyps. METHODS: Fifty hyperplastic and 50 adenomatous polyps received consecutively in the laboratory were categorized by nine histopathologists, and the level of agreement between all observers and the original diagnosis was assessed using kappa statistics. RESULTS: For the eight observers with 11 months or more experience in histopathology, there was a high level of agreement with kappa statistics ranging from 0.84 to 0.98. This process was performed rapidly with an average of 13 to 22 seconds spent on each case. One observer with only 6-weeks' experience of histopathology had a lower overall level of agreement with kappa statistics ranging from 0.46 to 0.54, but the performance on the later cases was much higher. CONCLUSIONS: The level of agreement in the distinction between hyperplastic and adenomatous colorectal polyps is high among histopathologists with at least moderate amounts of experience in histopathology. The one virtually naïve observer showed a marked learning response during the study without feedback on case outcome. This suggests that histopathologists are very reliable in assigning cases to distinct nominal categories and that learning of these processes occurs early in a histopathologist's career.

Audit of the histopathological diagnosis of non-neoplastic colorectal biopsies: achievable standards for the diagnosis of inflammatory bowel disease.

AIM: To assess the performance of a histopathology department in diagnosing inflammatory bowel diseases with comparison of reports from other centres. STUDY POPULATION: 1067 sets of endoscopic biopsies received in the department of histopathology, Royal Hallamshire Hospital, 1990-1995. METHODS: The histopathological diagnosis of non-neoplastic endoscopic colorectal biopsies was audited using data from histopathology reports. The biopsy diagnosis by the initial reporting pathologist and final diagnosis after additional investigations (endoscopy, radiology, microbiology) or surgery were used to derive sensitivity, specificity, and positive predictive values for categories of disease. RESULTS: Diagnosis was validated for 1067 biopsy sets (43% of those initially assessed). For all biopsies (with or without active inflammation) reports highly suggestive or suggestive of Crohn's disease had a sensitivity of 50%; for ulcerative colitis the comparable figure was 62%. Sensitivity was the same for both diagnoses (74%) in those biopsies with active inflammation. Positive predictive values for highly suggestive diagnoses of ulcerative colitis or Crohn's disease were 100%. In all biopsies the specificity of a histopathological diagnosis of normality was 96%. CONCLUSIONS: These results compare favourably with the other published audits and present an achievable level of performance for non-specialist hospitals with non-specialist histopathology services.

Evaluation of a statistically derived decision tree for the cytodiagnosis of fine needle aspirates of the breast (FNAB).

A decision tree for the diagnosis of FNAB was derived from defined human observations using a rule induction method, C4.5 (a derivative of the ID3 algorithm). This algorithm is an implementation of the top-down induction method where the tree is determined iteratively by adding those nodes and branches which maximize the information gain at each step. The tree was derived from a training set of 200 FNAB with known outcome using 10 defined features (from one observer) and patient age. The tree contained a total of seven nodes (six observable features and patient age) with eight endpoints (four benign, four malignant). The tree was applied to a test set of 400 further FNAB with observations from the training observer and produced a sensitivity of 95%, specificity of 93% and a positive predictive value (PPV) of a malignant result of 89%. Four trainee pathologists were given a training session on the observable features and then used the tree to determine outcome in a further 50 FNAB. The observers were blind to clinical details apart from age and the endpoints were coded with letters and not labelled benign or malignant. The results from these observers produced ranges of sensitivity 80-96%, specificity 64-92%, PPV 73-92% and kappa statistics (with known outcome) 0.6-0.8. Reported difficulties in using the tree included estimation of nuclear size. These results were worse than the performance of the observers on a further 50 cases without using the decision tree (sensitivity 80-100%, specificity 72-100%, PPV 78-100%, kappa 0.72-0.92). The original 50 case test set was rerandomized and the four trainee observers made all 10 defined observations on each specimen without using the decision tree; these observations were then used to derive decisions from the tree. The performance from this method was similar to that using selected features from the tree, suggesting that observation of all features together does not improve the reliability of each specific observation. The poor performance of this tree suggests that this methodology may be unsuitable for producing decision support aids for diagnostic or training purposes in this domain.

Does funeral preference influence clinical necropsy request outcome?

Attitudes towards necropsy have been shown to be more favourable amongst those relatives preferring cremation as a method of disposal compared to those with a preference for burial. In a two-year retrospective study, no significant relationship was found between funeral preferences (burial or cremation) and clinical necropsy request outcome when age, sex and religion were taken into account. Potential religious objections to necropsy were infrequent and cremation was found to have become the most popular method of disposing of the dead during a period when local clinical necropsy rates have continued to decline. Funeral preference is unlikely to have been a significant factor in the decline in clinical necropsy rates.