Urothelial papillary lesions. Development of a Bayesian Belief Network for diagnosis and grading.

The diagnosis and grading of urothelial papillary lesions are affected by uncertainties which arise from the fact that the knowledge of histopathology is expressed in descriptive linguistic terms, words and concepts. A Bayesian Belief Network (BBN) was used to reduce the problem of uncertainty in diagnostic clue assessment, while still considering the dependencies between elements in the reasoning sequence. A shallow network was designed and developed with an open-tree topology, consisting of a root node containing four diagnostic alternatives (papilloma, papillary carcinoma grade 1, papillary carcinoma grade 2 and papillary carcinoma grade 3) and eight first-level descendant nodes for the diagnostic features. Six of these nodes were based on cell features and two on the architecture. The results obtained with prototypes of relative likelihood ratios showed that belief in the diagnostic alternatives is very high and that the network can identify papilloma and papillary carcinoma, including their grade, with certainty. In conclusion, a BBN applied to the diagnosis and grading of urothelial papillary lesions is a descriptive classifier which is readily implemented and allows the use of linguistic, fuzzy variables and the accumulation of evidence presented by diagnostic clues.

Prostate tissue and serum markers.

Serum prostate specific antigen (PSA) is elevated beyond the arbitrary cut-off point of 4.0 ng/ml in the majority of patients with prostate cancer (PCa). It may also be greater than 4.0 ng/ml in some benign conditions, including benign prostatic hyperplasia (BPH). Therefore, serum PSA lacks high sensitivity and specificity for PCa. This problem has been partially overcome by calculating several PSA-related indices (such as PSA density, PSA velocity, percent free PSA) and/or evaluating other serum markers (such as human glandular kallikreins and prostate specific membrane antigen). Atypical small acinar proliferation (ASAP) often represents the underdiagnosis of cancer in biopsy material; patients with cancer on the repeat biopsy usually have an elevated serum PSA. Whether the determination of serum PSA can be of help in the identification of patients with isolated prostatic intraepithelial neoplasia (PIN), i.e., long before PCa develops, is still being debated

Microvessel quantitation in intraductal and early invasive breast carcinomas.

OBJECTIVE: To study the angiogenic process in intraductal carcinoma of the breast, with and without a small focus of stromal infiltration, and to compare the microvessel density between the in situ phase and the early infiltration phases of breast cancer. STUDY DESIGN: Microvessel density (number of microvessels per square millimeter of neoplasia) was quantitatively evaluated on anti-factor VIII-immunostained histologic sections obtained from 10 ductal carcinomas in situ (DCIS) (category A), 22 DCIS with a small focus of stromal infiltration (category B), 10 microinvasive carcinomas (category C), 12 T1a carcinomas (category D) and 20 T1b carcinomas (category E). RESULTS: The five categories of lesion had different values for microvessel density (P = .0017). Category A had microvessel density lower than category B (P = .0005). Category B had microvessel density higher than categories C, D and E (P = .0028, .0133 and .0033, respectively). CONCLUSION: Microvessel density seems to be a feature related to each crucial step in the early phases of neoplastic progression.

Morphometric index of adult renal cell carcinoma. Comparison with the Fuhrman grading system.

Various grading systems have been proposed for renal cell carcinoma (RCC), using nuclear, cytoplasmic, and architectural features. The available evidence suggests that nuclear grading is a better prognostic indicator than other types of grading schemes. Nuclear morphometry may still improve the correlation of the nuclear grading with survival, however, because observer consistency is lacking in the subjective grading of RCC. The aim of this study was to investigate morphometrically whether RCC cases show a continuous spectrum of nuclear changes or whether there are discrete groups of cancer that correspond to the four Fuhrman grades. Karyometry was performed on 5- microm-thick, haematoxylin- and eosin-stained sections from 60 cases of conventional (clear cell) RCC. The analysis also included the evaluation of normal renal tissue (proximal tubules) adjacent to cancer. In each case the difference between the value of the cancer and the corresponding normal epithelium was calculated to represent, quantitatively, the degree of similarity between the tumour tissue and the internal normal control. When the differences were sorted into ascending order, a steady increase in values was observed for both the nuclear and the nucleolar features. A monotonic trend was evident for the differences in the mean maximum nuclear diameter and mean nucleolar area. When the differences between the values in the cancer and in the corresponding normal epithelium of these two features were summed up, the method resulted in a continuous variable, or nuclear morphometric index, related to the degree of deviation of each individual RCC from its internal normal control. The lowest index values were observed in of Fuhrman grade I cases, whereas values ranging from 2.679 to 5.422 were associated with cases graded II. Values equal to or higher than 5.951 were seen in the cases assigned to either grade III or grade IV. Partial overlap was present between the index values in grades III and IV. The RCC cases can be represented by a continuous index that corresponds to the morphological grading based on the Fuhrman scheme. This study shows that the index may be useful in supplementing the pathologist's grading. This issue can be further addressed with follow-up studies.

Chromatin texture analysis of cortical adrenal gland adenomas, including incidentalomas, and adjacent normal-appearing cortical tissue.

OBJECTIVE: To describe, by morphometric and chromatin texture analysis, a series of adrenal gland lesions, including Cushing's and Conn's adenomas and incidentalomas. STUDY DESIGN: The material for the study consisted of five consecutive cases of incidentaloma, three cases of Conn's adenoma and three cases of Cushing's adenoma. Also included were five cases of adrenal carcinoma. Sections were stained according to the Feulgen procedure. Measurements were taken from the nodules and from two different zones, identified as outer and inner parts, of the normal-appearing adrenal cortex adjacent to the tumor. Data on approximately 50 nuclei were recorded for each of these three sites (tumor and outer and inner normal-appearing adrenal cortex). The nuclei were subjected to feature extraction and were analyzed by identification procedures--i.e., establishing nuclear and lesion signatures. RESULTS: The total optical density (OD) distributions of the nuclei from the normal-appearing adrenal cortex pointed to their diploid or near-diploid nature. In incidentalomas there was a very small increase in the number of nuclei, with increased total OD. In Conn's adenoma there was a noticeable but modest extension of the total OD distribution into the higher OD range. This trend continued for Cushing's adenoma. The pixel OD histograms for nuclei from normal-appearing tissue and from incidentalomas were hardly distinguishable. Starting with nuclei from Conn's adenoma, a shift toward lower pixel OD values began. The trend continued for nuclei from Cushing's adenoma and was very pronounced for nuclei from carcinoma. The nuclear signatures showed no appreciable difference between nuclei from normal-appearing cortex and from incidentaloma. Nuclei from Conn's adenoma were more similar to those from normal tissue in their signatures than nuclei from Cushing's adenoma. In fact, the nuclear signatures from Cushing's adenoma were almost identical to those of carcinoma. The lesion signatures for normal tissue, incidentaloma and Conn's adenoma confirmed the results seen in the nuclear signatures. There was a very modest increase in the number of nuclei with greater deviation from normal in incidentalomas, and the trend was more obvious in Conn's adenoma. However, in Cushing's adenoma there was a very substantial increase in the number of nuclei, with large deviations of their nuclear chromatin texture from normal. CONCLUSION: Computer-assisted analysis of nuclear characteristics proved useful in identifying and describing differences between groups of tumors arising in the adrenal cortex and highlighted the similarity between incidentalomas and adjacent normal-appearing cortex and between Cushing's adenoma and adrenal carcinoma.

Nuclear changes in the normal-looking columnar epithelium adjacent to and distant from prostatic intraepithelial neoplasia and prostate cancer. Morphometric analysis in whole-mount sections.

Subtle morphological changes and molecular alterations have been reported in normal-appearing tissue in prostates with high-grade prostatic intraepithelial neoplasia (PIN) and prostate cancer (PCa). The severity and the distribution of these changes and alterations within the prostate gland have not been addressed in previous publications. The aim of this study was to investigate morphometrically the nuclear changes of the normal-looking columnar epithelium adjacent to and distant from high-grade PIN and PCa. Karyometry was performed on the whole-mount histological sections of three radical prostatectomy (RP) specimens. Two concentrical lines, one corresponding to the outer surface (or capsule) of the prostate and the other corresponding to one centimeter towards the center, were drawn with a black pen on each whole-mount section. The part of the prostate tissue between these two boundaries was then divided into twelve equal sectors or regions. The part within the inner line was divided into two regions. The analysis was also performed on the slides of the apex and base of the prostate. One prostate contained normal-looking epithelium only (case no. 1). Another contained both high-grade PIN and PCa, the former occupying larger areas than the latter (case no. 2). Both high-grade PIN and PCa were present in the third sample, in which PCa was more widely distributed than PIN (case no. 3). The lesion measured in each region was always the most severe, e.g., either high-grade PIN or PCa. When neither were identifiable, then the normal-looking columnar epithelium was analyzed. For each sector, the mean and standard deviation of the nuclear area, maximum nuclear diameter, nuclear roundness factor, and nucleolar area were calculated. In normal-looking columnar epithelium, the mean of the mean nuclear area of the sectors of case no. 1 was 35.19 microm2 (SD 4.14). The mean nuclear areas in cases no. 2 and no. 3 were 37.94 microm2 (SD 4.65) and 37.31 microm2 (SD 4.36), respectively. The mean of the mean nuclear area of the sectors with high-grade PIN of case no. 2 was 49.85 microm2 (SD 8.44), whereas it was 54.26 microm2 (SD 2.91) in case no. 3. The mean of the nuclear area values obtained in the sectors of cases no. 2 and no. 3 with PCa was 56.74 microm2 (SD 6.56) and 61.17 microm2 (SD 8.13), respectively. When considering the normal-looking tissue of the second and third case, 79% and 90%, respectively, of the regions showed nuclear area values greater than 34.94 microm2 (e.g., the 50th percentile of the mean nuclear area values of the regions of the first case). Sectors with normal-looking epithelium, whose nuclear area was above this threshold, were both adjacent to and at a distance of more than 1 cm from those with PIN or PCa. The other nuclear features showed a similar trend of value changes. This study demonstrates that the normal-looking ducts and acini from prostate harboring preneoplastic and neoplastic lesions show morphological nuclear abnormalities that are not seen by the human eyes but that can be detected with image analysis. Such changes may be of diagnostic importance, especially in cases where clinical suspicion for cancer prevails after a negative biopsy.

Changes in the normal-looking epithelium in prostates with PIN or cancer.

BACKGROUND: In prostatic neoplasia, the time from tumour initiation and progression to invasive carcinoma often begins in men in the fourth and fifth decades of life and extends across decades. Until recently, the events initiating the process and the developments concomitant with the evolution towards invasive disease were largely unknown. METHODS: Quantitative and analytical methods are applied to provide insights into certain individual molecular events and their effects on the complex multiple feedback system of cellular metabolism and regulation in prostate neoplasia. RESULTS: Prostatic intraepithelial neoplasia (PIN) and prostate cancer (PCa) are associated with or possibly preceded by changes in the chromatin of secretory cell nuclei. The changes are detectable with a Bayesian belief network and quantifiable by computer image analysis in prostatic tissue that still appears histologically normal. In addition, normal looking prostate epithelium shows some molecular changes similar to those present in the associated preneoplastic and neoplastic lesions. Such changes are also occasionally present in normal prostate glands without PIN and cancer. CONCLUSIONS: The subtle morphological and molecular changes of normal looking epithelium might be seen as the onset of the development of prostatic neoplasia.

Prostatic intraepithelial neoplasia and prostate cancer: analytical evaluation.

For urologists and pathologists one of the two main issues in prostate pathology is the identification of those prognostic factors that could predict the exact outcome of individual patients with prostate cancer (PC). Therefore, the goal is to tailor the therapeutic approach to the clinical, morphological and biological features of each patient. The other issue involves the early detection of PC, preferably in the preinvasive phase, in order to treat the patient efficaciously. For this reason, understanding the biology of preinvasive or precursors lesions has become increasingly important. Prostatic intraepithelial neoplasia is only one of these lesions, and the best known to date. The role of others, such as atypical adenomatous hyperplasia, is considered as worth exploring. Prostatic intraepithelial neoplasia (PIN) represents the putative precancerous end of the morphologic continuum of cellular proliferations within prostatic ducts and acini. Two grades of PIN are identified (low grade and high grade), and high grade PIN is considered the direct precursor of invasive carcinoma. The continuum which culminates in high grade PIN and early invasive cancer is characterised by basal cell layer disruption, basement membrane disruption, progressive loss of markers of secretory differentiation, increasing nuclear and nucleolar abnormalities, increasing proliferative potential, and increasing variation in DNA content (aneuploidy). Clinical studies suggest that PIN predates carcinoma by ten years or more, with low grade PIN first emerging in men in the third decade of life. The clinical importance of recognising PIN is based on its strong association with carcinoma; its identification in biopsy specimens of the prostate warrants further search for concurrent invasive carcinoma. The issue of precursors of prostate cancer has several facets which reflect the multiplicity of patterns and variants of PC. A big step forward in understanding some basic aspects has already been made, especially in relation to PIN. More will be available soon. A large contribution to the management of isolated PiN lesions found in prostate biopsies is expected from molecular pathology and quantitation analysis.

Diagnostic distance of high grade prostatic intraepithelial neoplasia from normal prostate and adenocarcinoma.

OBJECTIVE: To develop a distance measure based methodology to support the morphological evaluation of high grade prostatic intraepithelial neoplasia (PIN), a direct precursor of prostate cancer. METHODS: Eight morphological and cellular features were analysed in 20 cases of high grade PIN found in radical prostatectomy specimens from patients with adenocarcinoma. The diagnostic distance was evaluated to measure the extent to which the feature outcomes of the individual high grade PIN cases differed from the expected outcome profile of normal prostate, low and high grade PIN, and cribriform and large acinar adenocarcinoma. The belief value for high grade PIN was evaluated with a Bayesian belief network (BBN). RESULTS: Complete separation existed between the cumulative absolute diagnostic distances of these 20 cases from the prototype feature outcomes of high grade PIN and normal prostate the values for which were < or = 3 (range 0 to 3) and > or = 9 (range 9 to 15), respectively. The distances from low grade PIN (range 3 to 9), cribriform adenocarcinoma (range 2 to 8), and large acinar adenocarcinoma (range 5 to 10) were intermediate and showed overlap in their distribution. When taking into consideration whether the severity of feature changes was increasing or decreasing in comparison with the category prototype outcomes, the cumulative directional diagnostic distances from high grade PIN ranged from -3 to +3. Positive distance values were seen relative to low grade PIN (range +3 to +9) and relative to normal prostate (range +9 to +15). Negative values were found relative to cribriform adenocarcinoma (range -8 to +2). The distance values from large acinar adenocarcinoma ranged from -2 to +4 and partly overlapped with those from the high grade PIN category. A bivariate scattergram derived from both diagnostic distance measures showed excellent separation between the groups' distances. BBN analysis confirmed the morphology based diagnosis. The distance evaluation resulted in 18 cases whose belief value for high grade PIN ranged from 0.60 to 0.87. In the remaining two cases the results of the BBN analysis showed a belief value of 0.50 and 0.57 for low grade PIN and of 0.49 and 0.38 for high grade PIN, respectively. CONCLUSIONS: Distance measure based methodology represents a useful diagnostic decision support tool for the accurate evaluation of high grade PIN.

Meningioma: the impact of new techniques for the diagnosis and prognosis.

Our knowledge of meningioma has expanded considerably in the last few years. Immunohistochemistry, cytogenetics and molecular biology have given an important contribution to this improvement. Meningiomas can have almost endless variations in cellular morphology, architectural patterns and metaplastic changes. The majority of them have no prognostic implications. But a few variants should be recognised because of peculiar clinico-pathologic correlations or biological behavior. Histological features useful in distinguishing benign from potentially aggressive meningiomas have been identified. According to the WHO classification meningiomas are classified as benign (Grade 1), atypical (Grade 2) and anaplastic (Grade 3). Since histological appearance fails to predict accurately the clinical behaviour in a significant percentage of meningiomas, the attention has turned from tumor histology to tumor biology. Proliferative indices can be used, together with other histologic features, in assessing the prognosis as well as the postoperative management of the patients. Karyotyping may be of use to identify a subgroup of patients at higher risk for recurrence who may need special follow-up and treatment. The most consistent chromosome aberration in meningiomas seems to be a monosomy 22. As the karyotype becomes progressively abnormal, the tumor becomes more aggressive. Molecular genetic analysis has shown that TP53 gene mutation may be considered as a marker for malignant transformation in meningioma. P53 immunoreactivity is not always associated with the gene mutation but is not detectable in benign meningiomas.