Assessment of dysplasia in colorectal adenomas: an observer variation and morphometric study

Diagnostic variability in the histopathological assessment of advanced colorectal adenomas and early colorectal cancer in a screening population

Aim

The aim of this study was to evaluate interobserver variability between individual pathologists and a panel of pathologists in the histopathological assessment of advanced colorectal neoplasms in the Dutch bowel cancer screening population.

Methods and results

Histological slides of adenomas with high‐grade dysplasia and early colorectal carcinomas (CRC) from 20 different laboratories were reviewed by the pathology panel of the Dutch bowel screening programme. Interobserver variability was reported by descriptive statistics. In addition, potential clinical consequences of discrepancies were evaluated. A total of 104 cases of adenomas with high‐grade dysplasia and 83 early CRCs were reviewed. Discrepancies were observed in 41 of 104 (39.4%) adenoma cases, which potentially had clinical consequences in 16 (15.4%) cases. For CRC, discrepancies were shown in 44 of 83 cases (53.0%) and would have potentially led to alternative treatment strategies in 25 (30.1%) cases. Most frequently, discrepancies were observed in the assessment of lymphovascular invasion (23 of 73 cases, 31.5%).

Conclusion

This study showed that considerable interobserver variability is present in the histopathological assessment of advanced colorectal neoplasia, which may impact upon treatment choices. Additional stains and education, as well as intercollegial consultation, might decrease this variability.

Decrease of variation in the grading of dysplasia in colorectal adenomas with a national e-learning module

AIMS

Variation in health-care is undesirable, as this is potentially harmful for patients. In the Netherlands, an e-learning module was developed to standardise pathological evaluation of colorectal adenomas. We studied the effect of e-learning on interlaboratory variability in grading of dysplasia in screened conventional colorectal adenomas.

METHODS AND RESULTS

A cross-sectional retrospective study was performed, including all colorectal adenomas from the Dutch population-based colorectal cancer screening programme, retrieved from the Dutch Pathology Registry (PALGA) from January 2014 to July 2015. The e-learning tool, commissioned by the National Institute for Public Health, was implemented among screening pathologists from October 2014. Proportions of high-grade dysplasia (HGD) were compared before (January-July 2014) and after implementation (October 2014-July 2015) of the e-learning module. Interlaboratory variation was assessed by multilevel mixed-effects analysis. In total, 20 713 colonoscopies (20 546 patients) were performed after a positive faecal immunochemical screening test, resulting in the inclusion of 56 355 conventional adenomas from 37 pathology laboratories. Before implementation, 12 614 adenomas were diagnosed, including 4.3% with HGD. After implementation, 43 741 adenomas were diagnosed, and the HGD proportion decreased to 3.9%. Univariable analysis showed less deviant proportions of HGD after implementation in 62% of the laboratories (P = 0.019). Multilevel analysis confirmed decreased variation in the risk of diagnosing HGD (P = 0.021).

CONCLUSIONS

Interlaboratory variability in grading HGD in colorectal adenomas after a positive screening test decreased after implementation of an e-learning module for pathologists. We therefore conclude that e-learning has a favourable influence on decreasing diagnostic variability, making this a relevant strategy for health-care standardisation.

Reproducibility of Histopathologic Diagnosis and Classification of Non-Melanocytic Skin Cancer: A Panel Exercise in the Framework of the Multicenter Southern European Study Helios

Aims and background

The reproducibility of histologic diagnoses, and in particular of the distinction between basal and squamous cell forms, has been evaluated in the framework of a multicenter case-control study (in Italy, France, Spain and Switzerland) aimed to assess the causes of non-melanocytic skin cancers.

Methods

A panel composed of 10 pathologists from the collaborating centers was appointed. A total of 1774 slides of routine diagnoses were blindly reviewed by a second panelist; discordant diagnoses underwent a third examination. Controversial and interesting cases were discussed during general sessions.

Results

The results showed a high degree of concordance (99.5%), with a Cohen's kappa of 0.85 (95% CI, 0.77–0.94) in the assessment of malignancy of lesions. The concordance in the distinction between large morphologic groups, basal cell carcinoma and squamous cell carcinoma was also high (Cohen's kappa = 0.85; 95% CI, 0.82–0.89). The assessment of histologic subtypes, degree of invasion and differentiation showed a lower degree of concordance, presumably as a consequence of a weaker consistency in the relevant classifications.

Conclusions

The reproducibility study has therefore validated the epidemiologic study and in particular allowed to correct some misclassifications that could have lessened the analysis of the case-control study. In general, because of its characteristics (number of pathologists and variety of their origins, the large number of cases examined, blind examination of histologic slides), the conclusions of the study may show a certain degree of generalization, at least with regard to the countries represented. Routine histologic diagnoses of cutaneous carcinoma showed a high degree of reliability with reference to the assessment of malignancy and the distinction between basal and squamous cell carcinoma morphotypes.

Interobserver agreement in the reporting of colorectal polyp pathology among bowel cancer screening pathologists in Wales

AIMS

To assess the interobserver agreement in the reporting of colorectal polyps among histopathologists participating in the Welsh Bowel Cancer Screening (BCS) programme.

METHODS AND RESULTS

Twelve benign polyps representative of BCS cases were identified from pathology files and reported by 28 BCS histopathologists using proforma sheets. The level of agreement between the participants and a gold standard was determined using kappa (κ) statistics. A moderate level of agreement was achieved in the reporting of polyp type [κ = 0.45; 95% confidence interval (CI) 0.34-0.59] and adenomatous lesions were distinguished from non-adenomatous lesions in 96% of cases. Substantial agreement was obtained in distinguishing low- and high-grade dysplasias (κ = 0.67; 95% CI 0.50-0.86), but there was only fair agreement in reporting excision margin status (κ = 0.24; 95% CI 0.07-0.43) with frequent use of the 'uncertain' category. Significant issues included categorizing serrated lesions, recognizing focal high-grade dysplasia and epithelial misplacement, and apparent overdiagnosis of villous change in adenomas.

CONCLUSIONS

Interobserver variability in some aspects of reporting colorectal polyps by BCS pathologists is suboptimal, with a potential impact upon patient management and the efficient running of the screening service. Approaches to addressing this are discussed.

Agreement in interpreting villous elements and dysplasia in adenomas less than one centimetre in size

BACKGROUND

Villous elements and dysplasia grade in small adenomas are used in many countries to guide post-polypectomy colonoscopy intervals.

AIMS

Measure agreement in interpretation of villous elements and dysplasia in small adenomas.

METHODS

Consecutive endoscopically resected adenomas <10mm in size (203 adenomas less than 6mm and 149 adenomas 6-9 mm in size) were reviewed by 3 expert gastrointestinal pathologists. Interpretations were compared to routine clinical pathology readings at our institution and to each other.

RESULTS

All pathologists used the same definitions for villous and tubular histology. The overall kappas for villous elements in <6mm and 6-9 mm adenomas were 0.29 and 0.26, respectively. Interpretation of dysplasia grade had kappas of 0.02 and 0.09 for adenomas <6mm and 6-9 mm, respectively. Two expert pathologists who used cytologic criteria had much higher fractions of high grade dysplasia compared to the third expert and the pathologists at our centre, who relied on architectural criteria.

CONCLUSIONS

Villous elements and dysplasia grade in small adenomas are problematic as determinants of post-polypectomy surveillance intervals. Uniform pathologic criteria for dysplasia grade are needed.

The evaluation of colon biopsies using virtual microscopy is reliable

AIMS

Virtual microscopy offers major advantages for pathology practice, separating slide evaluation from slide production. The aim of this study was to investigate the reliability of using whole slide images as compared with routine glass slides for diagnostic purposes.

METHODS AND RESULTS

Colon biopsies (n = 295) were assessed using both glass slides and whole slide images by four pathologists and two residents. Two pathologists scored the digital images of biopsies in a primary diagnostic setting. For each case, the consensus diagnosis was defined as the majority diagnosis on the study's glass slides. All diagnoses were grouped into seven main diagnostic categories, and further divided into subgroups. The overall concordance rates were 89.6% for whole slide images and 91.6% for light microscopy. The concordance rates of the subgroups 'adenoma' and 'adenocarcinoma' between whole slide images and conventional microscopy showed only small variability. The intraobserver (whole slide images versus glass slide) agreement, including subgroups, was substantial, with a mean κ-value of 0.78, and was higher than the interobserver agreement for glass slides (interobserver κ-value of 0.69).

CONCLUSIONS

This study shows good diagnostic accuracy and reproducibility for virtual microscopy, indicating that this technology can reliably be used for pathological evaluation of colon biopsies in a primary clinical setting.

Reproducibility of the villous component and high-grade dysplasia in colorectal adenomas <1 cm: implications for endoscopic surveillance

The presence of high-grade dysplasia (HGD) or villous component (VC) defines an advanced adenoma (AA) in patients with 1 or 2 adenomas <1 cm in size. Current consensus guidelines recommend that patients with AA undergo more intense postpolypectomy surveillance. In these clinical situations, the interobserver reliability in determining VC and HGD would play a major role in the credibility of these consensus guidelines. Therefore, the purpose of this study was to evaluate interobserver variability of VC and HGD in polyps <1 cm before and after the development of consensus criteria among gastrointestinal (GI) pathologists. Five GI pathologists independently evaluated 107 colorectal adenomas <1 cm, and classified them into tubular adenomas or adenomas with a VC (A-VC) and into low-grade dysplasia or HGD. Then a consensus conference was held and consensus criteria for VC and HGD were developed by group review. The same set of 107 slides were rereviewed independently by the same 5 GI pathologists. Interobserver variability using κ statistical analysis before and after the application of consensus criteria was assessed. A 1-sided z-test was used to determine whether κ scores increased after the consensus conference. Interobserver agreement before and after the consensus conference was poor for assessment of A-VC, HGD, and AA. These data calls into question the validity of basing clinical decisions on this distinction.

Advanced precancerous lesions (APL) in the colonic mucosa

Colorectal cancer is a leading cause of cancer death worldwide. Most colorectal cancers are preventable. Surveillance colonoscopy is used to detect and remove precancerous lesions. Although the majority of precancerous lesions develop sporadically, some have an inherited component. In this review, we summarize the clinical, pathologic, and molecular features of advanced precancerous lesions of the colon. The most common and clinically important intestinal polyposis syndromes, and their genetics, are also discussed. Finally, current recommendations regarding the treatment and surveillance of precancerous lesions, both in the sporadic and in inherited setting, are reviewed.

Diagnostic accuracy of community pathologists in the interpretation of colorectal polyps

BACKGROUND AND AIMS

Management of patients with endoscopically removed colorectal polyps is generally dependent on pathological evaluation. The aim of this study was to assess the accuracy and clinical impact of pathologic interpretation of colorectal polyps by community pathologists.

METHODS

Two expert gastrointestinal pathologists reviewed the slides of 300 colorectal polyps initially examined by 14 general pathologists. Polyps had been detected by a fecal occult blood test colorectal cancer screening program in Haut-Rhin, a French administrative district.

RESULTS

Villous histology was overread in 24.8% of cases and high-grade dysplasia in 22.0%. The diagnosis of serrated adenoma was confirmed in 15.7% of cases. The diagnosis of T1 carcinoma was overestimated in seven cases (17.9%) and missed in four. In the screening program, the proportion of correct diagnoses of community pathologists was estimated at 45.3% of polyps, of misclassification without clinical impact at 27.5%, and of misclassification with a theoretical impact on management at 27.2%, leading to over-surveillance in 20.3% of polyps and to unnecessary surgical resection in three individuals. Overall, 37.5% of the pathology reports of malignant polyps were complete, presenting all criteria necessary for therapeutic decision-making.

CONCLUSION

Community pathologists exhibited moderate accuracy for interpreting colorectal polyps, with an impact on patient management for around one out of five individuals. Our results confirm the intrinsic poor reliability of the pathologic interpretation of villous histology and high-grade dysplasia and suggest that these advanced pathologic features should be abandoned for clinical use. They illustrate the need for a clarification of the nomenclature of serrated polyps.

AGA future trends report: CT colonography

BACKGROUND & AIMS

Computed tomographic colonography (CTC) was first described more than a decade ago. Recent advances in imaging hardware and software and results of clinical trials based on new methods for performing and interpreting images suggest that CTC may now be assessed as a method for colorectal cancer screening.

METHODS

The Research Policy Committee of the American Gastroenterological Association assembled a task force to review the results of recent clinical trials and quantitative mathematical models pertaining to CTC. The goal of the task force was to assess the current knowledge about CTC and to evaluate the issues that will define its impact.

RESULTS

Limitations in evaluating the current state of CTC technology include a wide variation in results of clinical trials. There are as yet insufficient data on the use of CTC in routine clinical practice. Limitations in the use of quantitative mathematical models make predictions based on such models of limited value. The cancer risk and therefore clinical importance of small colorectal polyps detected by CTC and/or nonpolypoid neoplasia not detected by CTC remains largely unknown.

CONCLUSIONS

CTC is attractive as a colon imaging modality. It is therefore anticipated that CTC will have a significant impact on the practice of gastroenterology. However, the magnitude of the impact is currently unknown. Whether the ongoing implementation of CTC will increase or decrease the number of referrals for colonoscopy or shift the procedure from colorectal cancer screening to therapeutic interventions (e.g., polypectomy) is unknown at the present time. Multidisciplinary collaboration between gastroenterology and radiology to promote effective implementation and ongoing quality assurance will be important.

How accurate are subjective judgements of a continuum?

AIMS

To assess the accuracy of subjective judgements of a uni-dimensional continuum.

METHODS AND RESULTS

Twenty-four observers were asked to estimate the position of a dot placed between two lines using a 100-point scale. Each observer judged 20 different positions. Ninety-five percent of observations were between -7 and +9 of the true value. The median and the mean value of the estimates for each position were within one or two points of the true value in most cases with a maximum deviation of five. There was perfect correlation between the ranks of the median and the mean and the true value (correlation coefficient +1, P < 0.00001). The kappa values for interobserver agreement varied from 0.98 for two categories to 0.55 for 10 categories and 0.39 for 20 categories. Information transmitted increased from 0.98 bits with two categories to 2.83 bits with 20 categories.

CONCLUSIONS

The experiment indicates that subjective judgements can be accurate but it is necessary to use a large number of categories. One hundred-point scales allow confidence intervals to be calculated and the intervals are reduced if the results from several observers are pooled. The mean and the median of the judgements of a large number of observers are close to objective reality and this approach could be used to define a gold standard of rankings of pathological continua such as cervical dyskaryosis or tumour differentiation. There is a reciprocal relationship between kappa values and information transmitted which demonstrates the fallacy of using kappa statistics in studies of continua.

Severe dysplastic lesions in the colon - how aggressive should we be?

INTRODUCTION: Biopsies of colonic lesions are often reported as showing dysplasia, though in reality some lesions may harbour invasive malignancy. AIM: To assess the risk of underlying invasive malignancy in sessile polyps where biopsies had shown severe dysplasia and also to attempt to define a management strategy in such patients. METHODS: Between 1997 and 2001, 30 patients were diagnosed as having severe dysplasia using Morson's criteria in colonic lesions not amenable for endoscopic polypectomy. Severely dysplastic lesions were completely excised by appropriate surgical measures. RESULTS: Out of 30 patients, 15 had invasive cancers. Surgical intervention involved anterior resections, endoanal excisions, sigmoid colectomies, or abdomino-perineal excisions as deemed appropriate. The lesions ranged in size from 0.5 cm to 13 cm (mean 3.4 cm). There were nine T1 lesions (one of which was T1N1) and two each of T2, T3, T4 lesions (10 Dukes' A, 3 Dukes' B, 2 Dukes' C). Complete resection was confirmed histologically in all cases. One patient had a leak following endoanal excision, which required intervention. There was no mortality. DISCUSSION: This study demonstrates that endoscopic sampling can be misleading and severely dysplastic sessile lesions should be managed along the same principles as followed for invasive cancers, rather than adopting a 'wait and watch' policy with repeated endoscopies, biopsies or piece-meal polypectomies.

Inter-observer variation between general and specialist gastrointestinal pathologists when grading dysplasia in ulcerative colitis

Histological dysplasia is the cornerstone of colorectal cancer surveillance in ulcerative colitis (UC). Recently, pathologists have received unfavourable media attention concerning other cancer screening programmes. The aim of this study was to determine whether colonic biopsy specimens should be examined by gastrointestinal pathologists as opposed to generalists, by examining inter-observer variation between the two groups. Fifty-one coded slides showing varying degrees of dysplasia were mailed to seven gastrointestinal and six general histopathologists. Pathologists allocated each biopsy into one of four categories without the benefit of a clinical history or an opportunity to use the 'indefinite' category that is included in the Riddell classification. The responses were analysed using kappa statistics. The overall kappa statistic for gastrointestinal pathologists was 0.30 [95% confidence interval (CI)=0.26-0.34] and for general pathologists 0.28 (95% CI=0.23-0.32). Agreement was best for high-grade dysplasia (kappa of 0.54 and 0.61 for GI and general pathologists, respectively). There was total concordance of the 13 pathologists in only four of the 51 slides (7.8%) (95% CI=0.4-15.2%). It is concluded from these results that gastrointestinal pathologists are no better than generalists when grading dysplasia in UC and that agreement is poor in both groups. There is therefore no evidence that there would be any benefit in having specialist histopathology centres concentrating specifically on the interpretation of all surveillance colonoscopy biopsies from around the UK. It must be made clear to the public that surveillance and screening programmes carry a significant rate of histological error and that perfection cannot be expected or achieved with present methods.

Reproducibility of the WHO/IASLC grading system for pre-invasive squamous lesions of the bronchus: a study of inter-observer and intra-observer variation

AIMS

Although many workers have graded pre-invasive squamous lesions arising in the bronchus, there has been no consensus classification system until the latest edition of the WHO/IASLC histological classification of pulmonary and pleural tumours. Because the value of any such system is dependent on its reproducibility, we have circulated a series of such lesions to a panel of histopathologists to assess interobserver and intra-observer variation when the WHO/IASLC classification was applied.

METHODS AND RESULTS

Colour transparencies of 28 pre-invasive squamous lesions were assessed by six histopathologists (two with a special interest in pulmonary pathology, two generalists and two trainees) on three separate occasions over a period of 3 months, using the criteria of the WHO/IASLC (mild, moderate and severe dysplasia, and in-situ carcinoma). An additional category of metaplasia was added for those cases that showed no dysplasia. Weighted kappa coefficents of agreement (K(w)) were used to evaluate paired observations with a standard quadratic weighting being employed, such that kappa coefficients corresponded to intra-class correlation coefficients. Wilcoxon's sign-ranked test was used to measure the statistical significance of group trends, when comparing kappa values for the three grading systems. Various 3-point systems were also assessed, through combination of the above groups. Intra-observer agreement was substantially better than interobserver variation (mean: 0.71 vs. 0.55). Between the various pathologist groups, inter-observer variation was relatively minor, although intra-observer variation was higher within the trainee pathologist group. Using weighted kappa values, there was no significant difference in either inter-observer or intra-observer agreement between the five point grading system and a 3-point system of metaplasia/mild, moderate and severe/in-situ grades. However, there was a significant increase in variation when a 3-point system of metaplasia/mild, moderate/severe and in-situ carcinoma was used.

CONCLUSION

This study shows levels of interobserver and intra-observer variation similar to those found in other grading systems in histopathology, with no significant decrease in variability found by abridging the system. The WHO/IASLC system is therefore recommended for future use in both clinical and research fields.

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.

Magnetic resonance colonography versus conventional colonoscopy for the detection of colonic endoluminal lesions

BACKGROUND & AIMS

The most effective prophylaxis for colorectal cancer is endoscopic polypectomy. Prompted by the disadvantages of conventional colonoscopy (CC), we assessed the diagnostic ability of a promising alternative technique for detecting endoluminal masses: magnetic resonance colonography (MRC).

METHODS

Seventy consecutive patients referred for CC underwent preliminary MRC. The diagnostic ability of this technique in detecting colonic endoluminal lesions was determined, compared with that of CC, and related to the findings from histologic examination.

RESULTS

In detecting endoluminal lesions, MRC achieved a diagnostic accuracy similar to CC (sensitivity, 96%; specificity, 93%; positive predictive value, 98%; and negative predictive value, 87.5%).

CONCLUSIONS

MRC could be useful in screening programs of patients at high risk for colon cancer. Patients with MRC-detected endoluminal lesions must undergo CC for histologic diagnosis.

Grading and scoring in histopathology

In many areas of histopathology a nominal category, such as a diagnosis of breast carcinoma, does not give enough information for the referring clinician to make decisions about patient prognosis and treatment. Therefore scoring and grading systems have been developed which provide additional information. This article reviews the principles behind these systems with particular reference to the relationships between the natural clustering (or nonclustering) of cases and the imposition of arbitrary class boundaries on such distributions. The difference between real numbers and the ordinal categorical numeric labels, which are often produced by histopathology scoring systems, is discussed. The reproducibility of scoring and grading systems is reviewed and generic suggestions are given for developing new systems and for their validation.

The interrelationship between tubular and papillary sectors of tubulo-villous colorectal adenomas: comparative morphometric analysis and evaluation of cell proliferation

In a series of 100 colorectal adenomas, 23 tubulo-villous adenomas were individualized through the identification of papillae as structures persisting for more than 100 microm in serial sections with a connective axis lined with epithelial cells. In these adenomas, the tubular and villous areas with the highest dysplasia were selected, and a morphometric analysis was undertaken to assess the Index of Structural Atypia, the Nucleo-Glandular Index, and the Nuclear Stratification Index. The AgNor count and the proliferating cell nuclear antigen (PCNA) Label Index (LI) also were performed. The overall mean of each of these indexes was significantly higher in the villous sector than in the tubular one (P < .001). In 16 cases, the semi-objective method of dysplasia gradation showed a superior degree in the papillary sector, whereas it showed an equal degree in the remaining seven lesions. The AgNOR count was significantly different in all cases, with higher values in villous sectors (P < .05). With the exception of one case, this was confirmed by the PCNA LI. The Stratification Index showed significantly different values in 20 cases, whereas the other morphometric indexes showed a less discriminatory result. Our findings objectively show that the degree of dysplasia in tubulo-villous adenomas should be analyzed in the villous sector. The existence of heterogeneous cellular populations has been confirmed both in the structural organization of cells and in some basic parameters such as the cell proliferation rate in colorectal adenomas. Our findings suggest that the occurrence of villous architectural growth is a secondary event in a tubular adenoma. Enhanced cellular proliferation of the villous area allows the progressive substitution of tubular structures.

Predicting the risk of metachronous colorectal cancer in patients with rectosigmoid adenoma using quantitative pathological features. A case-control study

The prognostic value of quantitative pathological features in rectosigmoid adenomas was investigated, in search of more precise identifiers of adenoma-bearing patients at high risk of metachronous colorectal cancer. In a "nested case-control study" design, 21 cases with metachronous colon cancer during an average follow-up time of 16 years (range 3-30 years) after polypectomy and 67 controls were selected from a cohort of 1618 patients. The most advanced adenoma of each patient was analysed. Cases were matched with up to three controls simultaneously for size, grade of dysplasia, histological type, and number of adenomas, as well as for duration of follow-up. The patients did not undergo any post-polypectomy surveillance. Geometric characteristics of tumour nuclei, the arrangement of nuclei in the epithelium, and glandular changes were measured, and mitoses were counted. Several quantitative features measuring nuclear polymorphism and crowding showed significant prognostic value, while those measuring glandular changes and mitotic activity did not. A multivariate combination of the average distance between nuclei and the standard deviation of nuclear area discriminated an unfavourable group (n = 44) with 17 metachronous cancers from a favourable group (n = 44) with four metachronous cancers (P = 0*001, RR = 6*3). With the optimum cut-off, 28 patients without any metachronous cancer were discriminated from a group of 60 patients with 21 metachronous cancers. In conclusion, in the present study, quantitative pathological features assessed in rectosigmoid adenomas showed prognostic value additional to traditional measures. These features may therefore be useful in guiding post-polypectomy surveillance.

Management of dysplasia in the columnar-lined esophagus

The management of patients with high-grade dysplasia in Barrett's esophagus is complex and controversial with regard to electing continued endoscopic biopsy surveillance until an early adenocarcinoma is detected or proceeding with partial esophagogastrectomy. Clinical recommendations to patients for either option should be individualized and based on several parameters reflecting patient and clinician factors. Available data on interpretational variation in the diagnosis of dysplasia; limitation of diagnostic errors with the use of a rigorous, systematic endoscopic biopsy protocol; new information on the apparent benign natural history of high-grade dysplasia in some patients; and the morbidity and mortality of esophageal resection all suggest that recommendation for continued endoscopic biopsy surveillance is an appropriate clinical practice in selected patients. Ongoing research investigations on high-grade dysplasia in Barrett's esophagus aim to reduce the potential for diagnostic errors, simplify cancer surveillance, and develop therapeutic interventions that are safer than but as effective as surgery.

Stromelysin-3 expression in early (pT1) carcinomas and pseudoinvasive lesions of the colorectum

Pseudoinvasion in colorectal adenomas is often difficult to distinguish from invasive carcinoma. Previous studies have indicated that expression of stromelysin-3 (ST-3), one of the metalloproteinase family of enzymes, may be useful for the identification of early invasive carcinoma. The goal of our study was to detect ST-3 expression in colorectal adenomatous polyps to see if it could be helpful for the differential diagnosis of pseudoinvasion vs. true invasion. We studied 25 polypectomy specimens which were divided histologically into 2 groups; the first consisted of 15 adenomas with invasive carcinoma, 8 of these carcinomas were more diffusely infiltrative (pT1), and 7 tended to be expansively invasive. The second group was composed of 10 adenomas with pseudoinvasion. A 35S labelled cDNA probe was used for in situ hybridization (ISH) and a monoclonal antibody (5ST-4A9) for immunohistochemistry (IHC). The distribution of ST-3 expression as detected by IHC and ISH was identical. All diffusely infiltrative carcinoma cases showed ST-3 expression, but only focally in 2 cases with marked lymphocytic infiltration. None of the expansive carcinoma or pseudoinvasion cases showed ST-3 expression. ST-3 expression seems to be an indicator of invasion, but a negative reaction for ST-3 does not rule out an expansive invasive neoplasm or a diffusely infiltrative invasive tumour with a dense lymphocytic reaction.

Growth of colorectal polyps: redetection and evaluation of unresected polyps for a period of three years

BACKGROUND, AIMS, AND PATIENTS: In a prospective follow up and intervention study of colorectal polyps, leaving all polyps less than 10 mm in situ for three years, analysis of redetection rate, growth, and new polyp formation was carried out in 116 patients undergoing annual colonoscopy. The findings in relation to growth and new polyp formation were applied to 58 subjects who received placebo.

RESULTS

Redetection rate varied from 75-90% for each year, and was highest in the rectum and sigmoid colon. There was no net change in size of all polyps in the placebo group, however, polyps less than 5 mm showed a tendency to net growth, and polyps 5-9 mm a tendency to net regression in size, both for adenomas and hyperplastic polyps. This pattern was verified by computerised image analysis. Patients between 50 and 60 years showed evidence of adenoma size increase compared with the older patients, and the same was true for those with multiple adenomas (four to five) compared with those with a single adenoma. The new adenomas were significantly smaller and 71% were located in the right side of the colon. Patients with multiple adenomas had more new polyps at all the follow up examinations than patients with a single adenoma. One patient developed an invasive colorectal carcinoma, which may be evolved from a previously overlooked polyp. Two polyps, showing intramucosal carcinoma after follow up for three years, were completely removed, as judged by endoscopy and histological examination.

CONCLUSIONS

The results show that follow up of unresected colorectal polyps up to 9 mm is safe. The consistency of growth retardation of medium sized polyps suggests extended intervals between the endoscopic follow up examinations, but the increased number of new polyps in the proximal colon indicates total colonoscopy as the examination of choice. The growth retardation of the medium sized polyps may partly explain the discrepancy between the prevalence of polyps and the incidence of colorectal cancer.

Prospective audit of mucosal biopsy specimens of the gastrointestinal tract

AIMS

To determine why mucosal biopsy specimens of the gastrointestinal tract were taken and whether they were justified on clinical or pathological grounds.

METHODS

A prospective audit of 190 consecutive biopsy specimens received in a university hospital histology department over six weeks.

RESULTS

The 31 separate presenting symptoms included diarrhoea (34%), abdominal pain (16%) and rectal bleeding (15%). In 41% (78/190) the histology was normal, 28% (53/190) showed inflammatory changes and 11% 21/190) carcinoma. A clear justification for the procedure was identified in over 90% (171/190) of patients. In 36% (68/190) there was a change in patient management on receipt of biopsy reports and further investigations were ordered in 29% (55/190). The mean time taken to report biopsy specimens was 4.7 working days and there was no difference between the reporting time of a pathologist compared with a consultant or a trainee.

CONCLUSIONS

There is no evidence that mucosal biopsy specimens are taken unnecessarily.

The nonspecificity of histological findings reported for flat adenomas

Flat adenomas have been reported to be associated with an increased risk of high grade dysplasia and with a genetic predisposition to numerous colonic polyps. Histological findings reported for flat adenomas are dysplastic glands superficial to nondysplastic glands and a thickness of dysplastic mucosa that does not exceed twice that of nondysplastic mucosa. We assessed the specificity of these histological findings with regard to a colonoscopically flat appearance in a series of 127 sequentially accessioned adenomas from 52 patients without adenomatous polyposis coli or inflammatory bowel disease. Thirty-two of the 127 adenomas (25%) from 20 of 52 patients (36%) showed the histological findings outlined above; none of these polyps was grossly flat and none had high grade dysplasia. The predictive values of these histological features for patients younger than 50 years old and for the presence of five or more polyps in a patient were 15% and 25%, respectively. We conclude that the histological findings previously reported for flat adenomas are not specific for that entity and are not uncommonly seen in grossly typical appearing adenomatous polyps. These histological findings also are not associated with high grade dysplasia. They can be seen in polyps from individuals without clinically recognized polyposis, and are relatively poor indicators of young age or increased polyp number, features that could potentially indicate a clinically unrecognized polyposis syndrome. The histological findings in and of themselves thus appear to confer no additional cancer risk to the individual or to the individual's family members over and above that associated with an adenoma.

Observer variability in the assessment of type and dysplasia of colorectal adenomas, analyzed using kappa statistics

PURPOSE

The aim of this study was to establish the intraobserver and interobserver variability in the assessment of histologic type (tubular, villous, and tubulovillous) and grade of cytologic dysplasia (mild, moderate, and severe) in colorectal adenomas.

METHODS

One hundred eighty-seven slides of adenomas were assessed twice by three experienced pathologists, with an interval of two months. Results were analyzed using kappa statistics.

RESULTS

For agreement between first and second assessment (both type and grade of dysplasia), kappa values for the three specialists were 0.5345, 0.9022, and 0.4100, respectively. Agreement was better for type than for dysplasia. The strength of agreement was moderate for Observers A and C and almost perfect for Observer B. Agreement between all three observers was seen in 35.2 percent for both type and dysplasia in 61 percent for type and in 47.8 percent for dysplasia. The kappa values for Observer A vs. B and Observer C vs. B were 0.3480 and 0.3770, respectively (both type and dysplasia). Values for type were better than for dysplasia, but agreement was only fair to moderate.

CONCLUSION

The interobserver agreement was moderate to almost perfect, but the intraobserver agreement was only fair to moderate. A simpler classification system or a centralization of assessments would probably increase kappa values.

Fractal geometric analysis of colorectal polyps

Colorectal polyps have a subjectively self-similar structure which suggests that these structures may have fractal elements and that the fractal dimension may be a useful morphometric discriminant. The fractal dimensions of images from haematoxylin and eosin-stained sections of 359 colorectal polyps (214 tubulovillous adenomas, 41 'pure' tubular adenomas, 29 'pure' villous adenomas, 68 metaplastic polyps, and 7 inflammatory polyps) were measured using a box-counting method implemented on a microcomputer-based image analysis system. Results were assessed using polychotomous logistic regression, confusion matrices, and kappa statistics. All examined polyps were shown to have a fractal structure in the range of scales examined. The fractal dimension was significantly different between different diagnostic categories (P < 0.0001) and was a useful discriminant between these categories (kappa statistic 0.60 for the confusion matrix with size as the other variable). The fractal dimension did not shown any significant correlation with the grade of epithelial dysplasia (P > 0.05). This study shows that colorectal polyps have a fractal structure over a defined range of magnification and Euclidean morphometric measurements will be invalid outside precisely defined conditions of resolution and magnification. The fractal dimension is a better way of quantitating the polyp shape and is a useful morphometric discriminant between diagnostic categories.

Stereological assessment of architectural changes in dysplastic epithelium of colorectal adenomas

BACKGROUND

Against the background of developing quantitative prognostic indicators for the future risk of colorectal cancer in adenoma bearing-patients, the possibilities of stereological measuring techniques for providing objective measures of architectural changes in colorectal adenomas were examined.

MATERIAL AND METHODS

The haematoxylin-eosin stained tissue sections of 59 adenomas, of which 20 showed mild dysplasia, 20 moderate dysplasis, and 19 severe dysplasia, were assessed. Using a projection microscope equipped with a coherent test system that was specifically designed to analyze anisotropic tissue, the volume density of stroma, epithelium and lumen, the outer and the inner gland surface density, and the length density lumen were determined.

RESULTS

With respect to grading, significant differences in the means of the inner gland surface density and the length density lumen were found mainly between mild and severe dysplasia as well as between moderate and severe dysplasia. This was especially evident when considering the subgroup of tubular adenomas. Stepwise discriminant analysis resulted in an overall correct jackknifed classification of 81.3% when mild and moderate dysplasia cases were taken as one group, and were compared with the group of severe dysplasia cases. With respect to histological type, the volume density lumen and the outer surface density glands, were most favourable. These two features allowed for an 87.5% overall correct jackknifed classification of tubular adenomas, versus adenomas with villous components. The analysis time was roughly 30 minutes per polyp. Intra-observer reproducibility was satisfying, with CE-values < or = 5% for all variables. Inter-observer reproducibility tests were encouraging.

CONCLUSIONS

The application of stereological techniques can be worthwhile in assisting in the classification of colorectal adenomatous polyps. Such techniques could therefore be a useful tool to estimate the prognostic value of adenoma morphology with respect to the development of metachronous colorectal tumours.

Morphometric analysis of colorectal cancer

Thirteen nuclear and cellular morphometric variables were measured in 312 cases of colorectal adenocarcinoma. All variables, except nuclear shape factors, differed significantly (P < 0.001) between normal colorectal and tumor tissue. In adenocarcinomas, epithelial nuclei in well-differentiated mucosa tended to be elliptic, while those in poorly differentiated mucosa were more spheric. Increasing values of maximum nuclear and elliptic diameter were associated with progression from none to simple tubule configuration (P < 0.001), none to easily discerned nuclear polarity (P < 0.001), and expanding growth pattern (P < 0.001). Univariate survival analysis revealed that none of the morphometric variables was significantly related to patient survival. Multivariate regression analysis showed that no morphometric variable could add significantly to a model containing the variables of patient age, Dukes stage, and tumor differentiation. Morphometry may be useful in distinguishing malignant from normal tissue and degrees of differentiation, but it is of little prognostic value in colorectal adenocarcinoma.

Observer reliability in assessing villitis of unknown aetiology

AIMS

To evaluate observer variation in diagnosis of villitis of unknown aetiology.

METHODS

Fifty haematoxylin and eosin stained sections were circulated to three pathologists who were asked to assess if villitis was present. These slides, with an additional 20, were recirculated and reassessed by the same pathologists.

RESULTS

Intra-observer agreement was 84.7% (range 74--92%) and interobserver agreement was 81%. A conjoint review by the three pathologists revealed that sources of differences included the overlooking of isolated single or small numbers of affected villi, the difficulty in assessing stromal cellularity close to infarcted parenchyma, and apparent stromal hypercellularity in immature villi.

CONCLUSIONS

Experienced pathologists can show a significant interobserver variation in assessing villitis of unknown aetiology. Future studies on villitis of unknown aetiology should address the problem of observer reproducibility of diagnosis.

Cytonuclear morphometry in the assessment of dysplasia in colorectal adenomatous polyps. A pilot study

In order to objectify the degree of dysplasia, results of nuclear and cellular morphometry were compared with assessed grades of dysplasia in 32 colorectal adenomatous polyps. Of these adenomas 8 showed mild, 17 moderate and 7 severe dysplasia (according to blind duplicate assessments by two pathologists). Using a microscope video-overlay interactive digitizing measurement system, 100 nuclei were measured in each specimen according to a strict measurement protocol. In a stepwise discriminant analysis the best discriminating features appeared to be mean stratification index, N/C ratio, mean contour ratio and mean form AR. Overall with these features 65.6% correct jackknifed classification of the 32 cases could be achieved. On the other hand, a clear three-group distinction could not be obtained, even with the best set of discriminating features. Similarly to gastric dysplasia, the morphometric features might be used to design a two-grade (low, high) rather than a three-grade system to assess the degree of dysplasia. These findings make clear that objectifying the degree of dysplasia in adenomatous polyps is possible by means of interactive morphometric analysis.

Morphometric studies in rectal biopsy specimens from patients with ulcerative colitis: effect of oral 5 amino salicylic acid and rectal prednisolone treatment

Morphometric measurements were performed on rectal biopsy specimens from 10 normal control subjects and 33 patients with a relapse of distal ulcerative colitis before and after treatment for four weeks in a double blind controlled trial with oral eudragit S coated 5 amino salicylic acid (n = 12) or rectal prednisolone enemas (n = 15). Measurements were assessed using a computer aided measuring system and a counting technique. When untreated patients were compared with the control group there were significant decreases in the area and height of the surface epithelium, in the area of crypt epithelium, and in the ratios of goblet cells to epithelial cells and of surface epithelium to lamina propria. The vascular and lamina propria areas and the number of intraepithelial polymorphs were increased. Treatment with 5 amino salicylic acid and corticosteroids resulted in similar morphological improvements: there was an increase in the area and height of the surface epithelium and the ratios of surface epithelium to lamina propria and of surface to crypt cell height. The ratio of goblet cells to epithelial cells also increased after treatment, while the numbers of polymorphs in the surface and crypt epithelium and lumen decreased. In conclusion, computerised morphometry is valuable for the assessment of the treatment of patients with ulcerative colitis and that in the doses used both treatments were of similar efficacy.

Adenomas and hyperplastic polyps in screening studies

A survey is given of colorectal polyps detected in a prospective randomized screening study with the fecal occult blood test. It is demonstrated that colonoscopy in persons with positive Hemoccult-II tests results in detection of and removal of a higher number of adenomas than among controls. The strategy may, therefore, possibly be followed by a reduction of the incidence of colorectal cancer. Screen-detected adenomas were most often in males and were larger than among controls; they were most often in the sigmoid colon, whereas the rectum was the most frequent location for adenomas in controls. Eight percent of persons with screen-detected adenomas had some symptoms, which could be referred to adenomas, in contrast to 50% among controls. Hyperplastic polyps served as markers for adenomas in persons with positive Hemoccult-II as well as in controls with adenomas detected by colonoscopy; however, most persons with adenomas had no hyperplastic polyps. Endoscopic polypectomy did not result in any severe complications, but surgical removal in 2 of 22 patients proved fatal. The results presented are compared with those of other prospective randomized trials. The optimistic view--that the incidence of cancer may be reduced by polypectomy in persons with positive Hemoccult-II tests--stresses the importance of securing optimal colonoscopy service.

A combination of cytological and architectural morphometry in assessing regenerative hyperplasia and dysplasia in ulcerative colitis

Morphometry and stereology were used to assess the cytological and architectural characteristics of regenerative and dysplastic colorectal mucosal abnormalities in ulcerative colitis. Reproducibility of measurements was assessed and found to be good, confirming the objective and reproducible nature of morphometric analysis. Discriminant analysis between the morphometric features of regenerative mucosal change and low-grade dysplasia revealed the significant cytological and architectural variables from which a cytological and architectural score were derived. The architectural score was capable of classifying all of the cases into their correct diagnostic category, although a combination of the two scores provided better separation of cases. Probability density analysis was carried out so that probabilities of group membership could be allocated to cases, given their cytological and architectural scores. Discriminant analysis was also applied to low- and high-grade dysplasia. Important cytological and architectural variables were identified and used separately to derive scoring systems. In combination, the dual scoring of lesions was capable of separating low- from high-grade dysplasia, although overlap was still evident. Again, probability density analysis allowed the allocation of cases into one or other category, although a closer examination showed that such a rule could not successfully classify a new set of low- and high-grade dysplasia cases. Quantitative histological analysis of mucosal abnormalities is shown to be of use in the objective diagnosis of reactive and dysplastic change in patients with ulcerative colitis. The use of simple scoring systems and probability based allocation of cases promotes the future role of morphometric techniques in the diagnostic laboratory.

Observer reproducibility in grading dysplasia in colorectal adenomas: comparison between two different grading systems

The two most well known and well defined grading systems for dysplasia in colorectal adenomas were compared with regard to reproducibility. The Konishi-Morson system (KMS) operates with several histological and cytological variables and grades of mild, moderate, and severe dysplasia. The Kozuka system is based on the extent of nuclear pseudostratification and also has three grades of dysplasia (III-V). As the group of severe dysplasia is very large in this system, it was extended with two higher grades, similarly based on individual histological criteria, known hereafter as the extended Kozuka system (EKS). Fifty six adenomas were graded by two observers, each observer grading twice according to the KMS criteria and twice according to EKS criteria. Intraobserver reproducibility was excellent for the KMS and moderate for the EKS, but this was not significant. The overall interobserver reproducibility was similar (moderate) for the KMS and for the EKS. Kappa values for interobserver reproducibility on individual categories were excellent for severe dysplasia according to the KMS, but low for all other categories in both systems. By simplifying both systems into two groups a high reproducibility can be obtained, but this implies that all the original grades (III-V) for the EKS must be grouped together. It is therefore recommended that a simplified KMS is used for further studies on the biological importance of dysplasia and for comparison between histological changes and other markers for colorectal neoplasia.

Morphometric evaluation of fine needle biopsy of single thyroid nodules

Area, perimeter, maximum diameter and form factors of nuclei of FNABs of thyroid nodules were measured with a MOP Videoplan. 23 cases were selected from patients with a scintigraphically cold single thyroid nodule. The mean values of area, perimeter and maximum diameter were significantly different (p less than 0.001) between the adenoma and carcinoma cases; no differences were found for the form factors. Although the analyses gave significant results, a certain amount of overlap of the benign and malignant populations was present; therefore the significance of the standard deviation, assumed to be an index of variability of the nuclear area, was evaluated and this parameter was found to discriminate the two populations. The standard deviation of the nuclear area measured in 14 cases diagnosed as suspicious gave 77% accuracy in discriminating benign from malignant cases.

Differential expression of the Lewis Y antigen defined by monoclonal antibody C14/1/46/10 in colonic polyps

The expression of Le(y) (Lewis(y) Hapten), a difucosylated type 2 blood group-related antigen, in colorectal lesions was studied by using the monoclonal antibody C14. In normal colonic mucosa, strong staining has been observed in the terminal ileum, cecum, and ascending colon with minimal staining in the rest of the colon and rectum. Eighty-three percent of adenomas expressed Le(y), with 70% showing an increased expression of Le(y) compared with normal tissue. Only 25% of metaplastic (nonneoplastic) polyps showed an increased expression of Le(y). The expression of Le(y) in adenomas was correlated with both size and degree of epithelial dysplasia of the adenomas and also showed an association with histologic type. No correlation was found with the location and morphology of the adenomas. The most strongly related parameter was the degree of dysplasia. All adenomas with severe dysplasia showed increased expression of Le(y), with 83% showing marked expression. This finding was irrespective of their size or type. Adenomas which did not exhibit severe dysplasia showed increased expression in 66% of cases, but only 18% showed marked expression. These findings show that the expression of Le(y) in colorectal lesions is associated with features related to malignant potential. Le(y) expression may provide useful prognostic information in the assessment of colorectal polyps.

Histopathological assessment of bleeding from polyps of the colon and rectum

One hundred and twenty seven colorectal polyps were examined to assess histopathological evidence of recent and old haemorrhage to test the usefulness of faecal occult blood tests in detecting colorectal neoplasia, in particular premalignant adenomas. Evidence of haemorrhage was consistently found in adenomas but was rare in non-neoplastic polyps. Haemorrhage within adenomas was predominantly stromal and associated with dilated, congested vessels. Factors associated with more severe haemorrhage were size, pedunculation, and villous growth; the degree of epithelial dysplasia and the age and sex of the patient were not associated factors. Proximal polyps showed more old haemorrhage than rectal polyps, but there was no such difference for recent haemorrhage.

A morphometric assessment of transitional mucosa in the colon

Quantitative morphometric analysis was used in 10 resection specimens to assess so-called transitional mucosa immediately adjacent to colorectal carcinoma. Eleven nuclear and cellular variables were measured from the malignant epithelial area and from zones of increasing distance (1 cm) from the lesion. In addition, mean mucosal height was assessed for each zone. Morphometrical differences between the mucosa immediately adjacent to the malignant epithelium and that taken at some distance from it were determined by Mann-Whitney U tests. Transitional mucosa showed increased mucosal height but no nuclear differences from normal mucosa. Other work has shown that there are nuclear morphometric differences associated with premalignant conditions in the colon. Thus, the suggestion that transitional mucosa represents early neoplastic change cannot be supported.

Observer variation in the assessment of dysplasia in ulcerative colitis

Six histopathologists allocated 100 sections from patients with long-standing ulcerative colitis into four diagnostic categories, regular hyperplasia, reactive atypia, low-grade and high-grade dysplasia. Their allocations were analysed using kappa statistics, including Fleiss's multiple kappa for groups of observers, and agreement on specific diagnoses was explored by constructing a conditional probability matrix. The nature of their disagreements was investigated using coefficients for systematic and haphazard errors. Over the four diagnostic categories there was a wide range of pairwise agreement from a low of 49% up to 72% and kappa values were only 'fair' or 'moderate'. As expected, agreement over the two categories 'dysplasia' vs 'no dysplasia' was better, ranging from 68% to 84%, and for 'atypia present' (reactive atypia, low- and high-grade dysplasia) vs "no atypia' two pairings achieved over 90% and 11 pairings over 80% agreement. In view of its clinical importance, conditional agreement on high-grade dysplasia, pairwise agreement on this diagnosis ranged from 100% down to as low as 33%. However, most of these disagreements fell into the low-grade dysplasia category so that closer follow-up and further biopsies would still have been indicated. It is a truism that the basis for safe management is careful co-operation between clinicians and pathologists who have all the relevant facts and who know and trust one another's judgement. Thus, several aspects of the ideal diagnostic process cannot be evaluated in inter-observer studies and the element of artificiality should be borne in mind when applying the findings to diagnostic practice. Nevertheless, the low level of agreement on the diagnosis of high-grade dysplasia achieved by certain pairings of specialist pathologists is a disturbing outcome of this study. Inaccuracies should be minimized by a concensus approach and we therefore recommend referral of putative cases of dysplasia to interested pathologists for further opinions. We would also advocate that pathologists faced with appearances which are indefinite between reactive atypia and dysplasia, would do better to describe them in terms of "atypia, significance uncertain', so that closer surveillance is undertaken, rather than force them into more precise diagnostic categories which may be incorrect.

Morphometric study of normal and adenomatous pituitary somatotrophs in humans

Somatotrophs from ten pituitary adenomas were evaluated morphometrically by light and electron microscopy using the following parameters: a) nuclear, cytoplasmic and cell volumes; b) volume density, total volume, surface density, total surface and surface/volume ratio of secretory granules, mitochondria, rough endoplasmic reticulum and Golgi apparatus, and c) the number of secretory granules and mitochondria per micron3 of cytoplasm and per cell. The results were compared (p less than 0.05 and p less than 0.10) with those obtained from somatotrophs identified in five normal pituitaries. The data obtained indicate that: a) in the adenomas, the number of secretory granules per cell cannot be accurately evaluated from their apparent number in sectioned cell profiles; b) there are two basic sub-types of adenomatous somatotrophs defined according to the mean secretory granule diameter; cells in which granule diameter is inferior to 180 nm exhibit distinct morphological features such as nuclear pleomorphism, the presence of gross bundles of intermediate sized filaments or fibrous bodies in the cytoplasm and a variable number of secretory granules. Adenomas constituted mainly by these cells were found in younger patients, suggesting the more aggressive nature of these tumours, thus warranting close clinical follow-up of such patients; and c) in both types of adenomatous cells, the organelles directly involved in the secretory process, i.e., the rough endoplasmic reticulum and Golgi apparatus, are larger than in the control cells; however, the ratio between the surfaces of these two compartments does not differ among the three groups studied.

Architectural morphometry in ulcerative colitis with dysplasia

Semi-automatic image analysis was used to assess the architectural features of normal colorectal mucosa and ulcerative colitis with and without dysplasia. Eight measured and derived morphometric variables were compared with the histological grading. The main data-set variation was due to: (1) the area of mucosa and epithelium per unit length of muscularis mucosae; (2) mean mucosal and epithelial height; and (3) the percentage epithelium and number of crypts per unit length of muscularis mucosae. Discriminant analysis using the variables mean epithelial height and mean lamina propria area per unit length of muscularis mucosae separated normals (n = 10) from high-grade dysplasia (8). The classification rule allocated low-grade dysplasia (8) to the high-grade category and 60% of regeneration cases (10) to the normal mucosa group. Scatter plots of the two discriminating variables separated normal and regenerative mucosa from dysplasia. Histological review of overlapping cases allowed redesignation of a high-grade dysplasia lesion as low grade. Architectural morphometry may be of use in assessing premalignant mucosal changes in ulcerative colitis as a guide to patient surveillance and therapy.

DNA aneuploidy and cell proliferation in familial adenomatous polyposis

Two hundred and thirteen samples from 20 patients with familial adenomatous polyposis (FAP) were investigated by flow cytometry and the results compared with 100 sporadic adenomas. Eleven of the 20 (55%) yielded one or more DNA aneuploid samples with an overall incidence within FAP adenomas of 12%. Despite a similar level of DNA aneuploidy in sporadic adenomas, it was commonly detected at a smaller polyp size. The degree of cell proliferation was found to be similar in the two groups (median %S+G2 15.8% v 16.4%) but larger FAP adenomas demonstrated a higher level of cell proliferation than smaller adenomas. DNA aneuploidy had no value as a predictor of a synchronous carcinoma and appeared to be an early change in the development of carcinoma in these patients.