Diagnosis of prostatic intraepithelial neoplasia: Prostate Working Group/consensus report

Cribriform Patterned Lesions in the Prostate Gland with Emphasis on Differential Diagnosis and Clinical Significance

Simple Summary

A cribriform structure is defined as a continuous proliferation of cells with intermingled lumina. Various entities may have a cribriform morphology within the prostate gland, ranging from normal, to benign, to borderline and even to malignant lesions. This review summarizes the morphologic features of entities that have a cribriform morphology within the prostate gland, with an emphasis on their differential diagnosis, molecular profile and clinical significance. The basic aim is to assist the pathologist with challenging and controversial cases and inform the clinician on the clinical implications of cribriform morphology.

Abstract

Cribriform glandular formations are characterized by a continuous proliferation of cells with intermingled lumina and can constitute a major or minor part of physiologic (normal central zone glands), benign (clear cell cribriform hyperplasia and basal cell hyperplasia), premalignant (high-grade prostatic intraepithelial neoplasia), borderline (atypical intraductal cribriform proliferation) or clearly malignant (intraductal, acinar, ductal and basal cell carcinoma) lesions. Each displays a different clinical course and variability in clinical management and prognosis. The aim of this review is to summarize the current knowledge regarding the morphological features, differential diagnosis, molecular profile and clinical significance of the cribriform-patterned entities of the prostate gland. Areas of controversy regarding their management, i.e., the grading of Intaductal Carcinoma, will also be discussed. Understanding the distinct nature of each cribriform lesion leads to the correct diagnosis and ensures accuracy in clinical decision-making, prognosis prediction and personalized risk stratification of patients.

Relevance of dog as an animal model for urologic diseases

We utilize animal models in urologic research to improve understanding of urinary physiology, determine the etiology of many urologic diseases, and discover and test novel therapeutic interventions. Dogs have a similar urinary tract anatomy and physiology to human and they develop many urologic diseases spontaneously. This chapter offers detailed comparisons of urinary tract anatomy, physiology, and the most common urologic diseases between humans and dogs. Dogs offer a unique opportunity for urologic research because they can be studied in research colonies and in client owned cohorts. Dogs also are among a limited number of non-human species that require continence and socially appropriate urinary behaviors (ex. going to the bathroom outside, training to not have submissive urination, etc.). These features make dogs unique in the animal kingdom and make them an ideal animal model for urologic research.

Preneoplasia in the prostate gland with emphasis on high grade prostatic intraepithelial neoplasia

There are a variety of morphological patterns and processes that have been implicated in the pathogenesis of prostate cancer. Prostatic intraepithelial neoplasia (PIN), inflammation with or without atrophy, and adenosis (atypical adenomatous hyperplasia) have all been given candidate status as precursor lesions of prostatic adenocarcinoma. Based on decades of research, high grade prostatic intraepithelial neoplasia (HPIN), a proliferative lesion of prostatic secretory cells, has emerged as the most likely morphological pre-invasive lesion involved in the evolution of many but not all prostatic adenocarcinomas. In this manuscript, we briefly discuss other proposed precursors of prostatic adenocarcinoma and then focus on the history, diagnostic criteria and morphology of HPIN. The incidence of HPIN and its relationship to prostate cancer is reviewed. The differential diagnosis of large glandular patterns in the prostate is discussed in depth. Finally, we summarise the recent clinicopathological studies evaluating the clinical significance of HPIN and discuss follow-up strategies in men diagnosed with HPIN.

High-grade prostatic intraepithelial neoplasia (HGPIN) and topographical distribution in 1,374 prostatectomy specimens: existence of HGPIN near prostate cancer

PURPOSE

High-grade prostatic intraepithelial neoplasia (HGPIN) is believed to be a precursor of prostate cancer (PCa). This study evaluated whether HGPIN was located close to PCa in whole radical prostatectomy specimens (RPSs).

MATERIALS AND METHODS

We evaluated 1,374 prostate specimens from 1999 to 2010 using a cMDX-based map model of the prostate. The distribution of 10,439 PCa foci was analyzed and visualized on a heat map. The color gradient of the heat map was reduced to six colors representing the frequency classification of the relative frequency of PCa using an image posterization effect. We defined 22 regions in the prostate according to the frequency of PCa occurrence. Seven hundred ninety RPSs containing 6,374 PCa foci and 4,502 HGPIN foci were evaluated. The topographical association between PCa and HGPIN in the RPSs was analyzed by estimating the frequencies of PCa and HGPIN in 22 regions. A logistic regression analysis was performed to assess the odds ratios of HGPIN for the presence of PCa in 22 regions.

RESULTS

Fifty-eight percent of PCa specimens included HGPIN and had significantly more favorable Gleason scores, lower PSA levels and smaller relative tumor volumes than isolated PCa specimens. HGPIN (68%) and PCa (69%) were predominantly localized to the apical half of the prostate. HGPIN was mainly concentrated in the peripheral zone medial to regions with high PCa frequencies. Upon logistic regression analysis, HGPIN was a significant predictor of PCa co-existence in 11 regions.

CONCLUSIONS

HGPIN was located adjacent to PCa in whole RPSs. PCa concomitant with HGPIN had more favorable pathologic features than isolated PCa.

Precursors of prostate cancer

High-grade prostatic intraepithelial neoplasia (PIN) is the only accepted precursor of prostatic adenocarcinoma, according to numerous studies of animal models and man; other proposed precursors include atrophy and malignancy-associated changes (with no morphologic changes). PIN is characterized by progressive abnormalities of phenotype and genotype that are intermediate between benign prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. The only method of detection of PIN is biopsy because it does not significantly elevate serum prostate-specific antigen concentration and cannot be detected by ultrasonography. The mean incidence of PIN in biopsies is 9% (range, 4%-16%), representing about 115,000 new cases of isolated PIN diagnosed each year in the United States. The clinical importance of PIN is its high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent carcinoma, especially when multifocal or observed in association with atypical small acinar proliferation (ASAP). Carcinoma develops in most patients with PIN within 10 years. Androgen deprivation therapy and radiation therapy decrease the prevalence and extent of PIN, suggesting that these forms of treatment may play a role in prevention of subsequent cancer. Multiple clinical trials to date of men with PIN have had modest success in delaying or preventing subsequent cancer.

Morphological transition of proliferative inflammatory atrophy to high-grade intraepithelial neoplasia and cancer in human prostate

BACKGROUND

Inflammation has been implicated as a potential etiological agent in human prostate cancer (PCa). Proliferative inflammatory atrophy (PIA) in prostate consists of areas of glandular atrophy associated with chronic inflammation and epithelial cell proliferation. It has been suggested that PIA is a candidate precursor of prostate malignancy. We aimed to explore the morphological transition between PIA and co-existing high-grade prostate intraepithelial neoplasia (HGPIN) and/or PCa.

METHODS

Serial slides of 50 whole-mounted radical prostatectomies were studied with H&E staining and immunostaining of cytokeratin 5 (CK5), glutathione S-transferase pi (GSTP1), hepatocyte growth factor receptor (c-MET), CCAAT/enhancer binding protein beta (C/EBPbeta), and Ki-67. Utilizing immunohistochemical stains to examine HGPIN, PIA-merging HGPIN, and PIA-merging PCa lesions, respectively.

RESULTS

A total of 1,188 HGPIN lesions were identified, of which 17% (198) were in the morphological process of merging with PIA. Thirty-six PIA-merging PCa lesions were also detected. The atrophic epithelial cells in such merging lesions had increased Ki-67 index and an intermediate phenotype: increased expression for CK5, GSTP1, c-MET, and C/EBPbeta. In addition, clusters of atypical epithelial cell hyperplasia, that is, with nuclear enlargement, hyperchromasia, and prominent nucleoli, were found in 16 PIA lesions. Such clusters of atypical cells that meet the criteria for HGPIN still expressed CK5 and were adjacent to focal chronic inflammation.

CONCLUSIONS

Direct morphological transition between PIA and HGPIN and/or PCa was present. The atrophic cells in these merging lesions had an intermediate phenotype. Clusters of atypical epithelial cell hyperplasia might represent the earliest transition from PIA to HGPIN. Prostate 69: 1378-1386, 2009. (c) 2009 Wiley-Liss, Inc.

Contemporary clinical management of isolated high-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (HGPIN) is a premalignant lesion associated with increased risk of coexistent cancer or delayed progression to carcinoma. Extended biopsy schemes have improved the ability to rule out concurrent cancers, increased the detection of isolated HGPIN and removed the routine necessity for immediate repeat biopsy. As the natural history of HGPIN is poorly defined, and no non-invasive marker allows monitoring of progression to cancer, routine delayed interval biopsy should be considered in all patients. In this article, we present an overview of the existing literature on HGPIN and a proposed strategy for clinical management.

Prostatic ductal adenocarcinoma presenting as a urethral polyp: a clinicopathological study of eight cases of a lesion with the potential to be misdiagnosed as a benign prostatic urethral polyp

AIMS

Centrally located prostatic ductal adenocarcinoma can present as a single urethral polyp mimicking a benign polyp. Such lesions have not been formally studied.

METHODS AND RESULTS

Clinicopathological and immunohistochemical findings of eight cases were analysed. Patients (mean age 76 years) presented with urinary symptoms and haematuria. Mean serum prostate specific antigen (PSA) was 7.01 ng/mL (range 1.04-21). Single small polyps were seen on cystourethroscopy with a clinical diagnosis of benign polyps. The most common architectural patterns were cribriform and papillary. Five cases had mild cytological atypia, three of which were initially diagnosed as benign prostatic urethral polyps. All cases were positive for PSA and 34betaE12. Seven cases tested were positive for AMACR (a-methylacyl-CoA racemase), p63 and cytokeratin (CK) 7 and 70% for CK20. Proliferative activity defined as Ki-67 labelling index was high (mean 26%, range 20-35%). Adenocarcinoma, predominantly ductal, was found in other specimens in four patients.

CONCLUSIONS

Centrally located prostatic ductal adenocarcinoma has the propensity to mimic benign urethral polyps clinically and histopathologically. Basal cell immunostaining may not help with this distinction but AMACR is useful. Prominent glandular complexity including cribriform patterns, nuclear pseudostratification, at least mild atypia and a high Ki-67 index distinguish these lesions from prostatic urethral polyps.

My approach to intraductal lesions of the prostate gland

The morphologically heterogeneous (intra)ductal lesions of the prostate frequently present a diagnostic challenge, particularly when found within prostate needle biopsies. By current convention, all high-grade intra-acinar and intraductal neoplastic lesions of prostatic origin fall under the diagnostic umbrella term: prostatic intraepithelial neoplasm (PIN). Although a long-standing contentious issue, some lesions currently adhering to the diagnostic criteria of PIN may actually represent the intraductal spread of (generally high grade) invasive cancer. Illustrating this fact, the well-described ductal subtype of prostatic adenocarcinoma is frequently associated with conventional-type acinar adenocarcinoma, and has a tendency to propagate within adjacent intact prostatic ducts. Clearly, the misdiagnosis of lesions representing invasive disease as preinvasive has the potential for unfavourable clinical sequelae. As yet, however, many of these lesions have escaped the establishment of reliable morphologic criteria or immunohistochemical differentiation for diagnosis. By defining stringent architectural and cytonuclear features specific for each of these lesions, it may be feasible to separate potentially sinister lesions from the subset of traditional (preinvasive) PIN lesions with limited clinical urgency. This review discusses the (intra)ductal lesions of the prostate, along with their differential diagnoses. Given the current state of knowledge, a pragmatic approach to their effective reporting is outlined, taking into consideration the clinical implications, as well as current guidelines for treatment and follow-up.

Design and Progress of a Trial of Selenium to Prevent Prostate Cancer among Men with High-Grade Prostatic Intraepithelial Neoplasia

High-grade prostatic intraepithelial neoplasia (HGPIN) is generally regarded as a premalignant lesion that progresses toward prostate cancer. In light of the significant sequelae of prostate cancer treatment, prevention is desirable, and men with HGPIN would be suitable, high-risk subjects. There is in vitro, in vivo, epidemiologic, and human experimental evidence that selenium supplementation may protect against prostate cancer. This article introduces the rationale for, and progress to date, of a double-blind, randomized, placebo-controlled trial of selenium supplementation (200 mug/d in the form of selenomethionine), to prevent the development of prostate cancer among men with HGPIN. The trial, Southwest Oncology Group Protocol 9917, funded by a National Cancer Institute program supporting pivotal prevention trials has registered 537 patients and has randomized >380 to date. Subject accrual is expected to be completed by the fall of 2006, with trial completion in 2009.

Dealing with non-cancerous findings on prostate biopsy

Most prostate biopsies do not show malignancy. The proper management of non-cancerous pathologic findings of the prostate is controversial. For this article, we reviewed the current literature for indications for repeat prostate biopsy after initial biopsies demonstrated non-cancerous prostatic tissue or benign prostatic hyperplasia. This review includes discussions of management of asymptomatic prostatitis and how it may affect prostate-specific antigen, and also the management of several potentially premalignant lesions such as atrophy, atypical small acinar proliferation, and high-grade prostatic intraepithelial neoplasia. There is a paucity of randomized trials in this area and, considering the high number of biopsies with non-malignant findings, we conclude that more investigation is warranted in this area.

Epigenetic Heterogeneity of High-Grade Prostatic Intraepithelial Neoplasia: Clues for Clonal Progression in Prostate Carcinogenesis

High-grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of prostate adenocarcinoma, but the frequency and timing of epigenetic changes found in prostate carcinogenesis has not been extensively documented. Thus, the promoters of three genes (APC, GSTP1, and RARbeta2) involved in prostate carcinogenesis were tested by quantitative methylation-specific PCR in tissue DNA from 30 prostate carcinomas, 128 high-grade PIN lesions, and 30 normal prostate tissue samples dissected from 30 radical prostatectomy specimens using laser capture microdissection. The percentage of methylated alleles (PMA) was calculated for each gene, and hierarchical cluster analysis was used to define the degree of similarity of epigenetic alterations among the various samples. We found that PMA values of APC and RARbeta2 were higher than those of GSTP1 in all three types of tissue samples and median PMA values for all three genes were higher in prostate cancer. By cluster analysis, 26 of 30 prostate carcinomas and 82 of 128 high-grade PIN lesions were grouped in the "high methylation" branch, whereas 24 of 30 normal prostate tissue samples were allocated in the "low methylation" branch. Although high-grade PIN lesions are epigenetically more similar to prostate carcinoma than to normal prostate tissue, paired prostate carcinoma and high-grade PIN lesions did not always segregate together. We concluded that APC and RARbeta2 hypermethylation is frequent in normal prostate tissue and the progressive enrichment in cells carrying methylated alleles observed in high-grade PIN and prostate carcinoma is consistent with clonal progression. Because GSTP1 promoter methylation is mainly observed in prostate carcinoma and some high-grade PIN lesions, it represents an important marker for the transition of in situ to invasive neoplasia.

Recursive partitioning for risk stratification in men undergoing repeat prostate biopsies

BACKGROUND

The current study was performed to identify risk factors and risk groups for carcinoma detection in men undergoing repeat prostate biopsies.

METHODS

The medical records of all men who had a negative initial prostate biopsy and underwent at least one repeat biopsy between 1992 and 2003 were reviewed to extract age, race, family history of prostate carcinoma, body mass index, referral indication, all prostate-specific antigen (PSA) values, digital rectal examination, PSA density (PSAD), the presence of a hypoechoic lesion, and the presence of high-grade prostatic intraepithelial neoplasia (HGPIN) on initial biopsy. Risk factors for a subsequent diagnosis of prostate carcinoma were identified using the log-rank test and a stepwise, stratified Cox regression model. Based on the risk factors identified by Cox regression analysis, recursive partitioning was further used for risk stratification.

RESULTS

A total of 373 patients underwent 975 biopsy procedures. During a median follow-up of 37.0 months, prostate carcinoma was detected in 107 of 373 patients (28.9%). Independent predictors of a positive biopsy (P < 0.05) were PSA doubling time (PSADT), PSAD, referral indication, the presence of HGPIN, patient age, and family history of prostate carcinoma. Recursive partitioning identified 4 distinct risk groups that were characterized by their PSADT and PSAD and the presence of HGPIN and had estimated 2-year and 5-year carcinoma detection rates of 3 +/- 1% and 21 +/- 4%, 28 +/- 5% and 40 +/- 7%, 22 +/- 6% and 58 +/- 8%, and 66 +/- 9% and 100%, respectively.

CONCLUSIONS

The authors identified a series of independent risk factors for prostate carcinoma detection after an initial negative prostate biopsy and characterized clinically meaningful and distinct patient risk groups. Despite a negative initial biopsy, patients with high-risk features remain at risk for the detection of prostate carcinoma.

Incidentally detected prostate cancer in cystoprostatectomies: pathological and morphometric comparison with clinically detected cancer in totally embedded specimens

There are limited data regarding the pathological features of incidentally detected prostate cancer. Examination of cystoprostatectomy specimens obtained during bladder cancer treatment affords a unique opportunity to examine incidentally detected prostate cancer and determine its relationship with clinically detected prostate cancer obtained during radical prostatectomy. We compared the pathological findings of incidentally detected prostate cancer in 132 consecutive cystoprostatectomy specimens from patients treated for bladder cancer with a consecutive series of 228 radical prostatectomy specimens from patients treated for prostate cancer. All specimens were totally embedded and whole-mounted. Karyometry was evaluated in select subsets of patients from the study groups. Incidentally detected cancer was found in 42% of cystoprostatectomy specimens, and the cancers were of lower Gleason score and lower pathological stage with fewer positive surgical margins than in clinically detected cancers in age-matched radical prostatectomies. High-grade prostatic intraepithelial neoplasia (PIN) was present in 82% of radical prostatectomy specimens, in 70% of cystoprostatectomies with incidentally detected prostate cancer, and in 54% of cystoprostatectomies without prostate cancer. Mean nuclear and nucleolar area was lower in incidentally detected cancer and PIN when compared with clinically detected cancer and PIN, respectively, similar to the results with proliferative indices. We conclude that incidentally detected cancer is less aggressive than clinically detected cancer.

Should high-grade prostatic intraepithelial neoplasia change our approach to infravesical obstruction?

OBJECTIVES

To investigate whether coexistence of high-grade prostatic intraepithelial neoplasia (HPIN) should change our therapeutic approach to infravesical obstruction.

MATERIAL AND METHODS

Of 505 patients who underwent sextant transrectal ultrasonography (TRUS)-guided prostate biopsy, 65 (12.8%) had HPIN and 29 of them underwent prostatectomy (23 transurethral resection of prostate (TURP), 6 open) due to obstructive urinary symptoms. Patients without carcinoma were followed up with semiannual prostate-specific antigen (PSA) and digital rectal examination. After a follow-up of 24.8 +/- 11.0 months, 19 of 29 patients who accepted our call had another sextant biopsy.

RESULTS

Mean age and initial mean PSA values of 29 patients were 67.6 +/- 6.7 years and 9.26 +/- 5.91 ng/ml, respectively. The final pathological evaluation of the surgical specimens revealed 2 prostatic adenocarcinomas both in the TURP group. The remaining 27 (93.2%) patients were found to have benign prostatic hyperplasia (BPH) and their serum PSA levels declined from 9.26 +/- 5.91 to 4.59 +/- 2.0 ng/ml 3 months after prostatectomy. Of the 19 patients who had another biopsy with a mean PSA value of 4.06 +/- 4.61 ng/ml, 15 and 4 of them had BPH and HPIN respectively.

CONCLUSIONS

Our preliminary data indicate that the presence of HPIN on TRUS-guided biopsies is not a factor to delay an indicated surgical intervention for infravesical obstruction.

Karyometry detects subvisual differences in chromatin organization state between cribriform and flat high-grade prostatic intraepithelial neoplasia

This digital texture analysis-based study evaluates the chromatin organization state in flat and cribriform high-grade prostatic intraepithelial neoplasia (PIN), in the adjacent normal looking secretory epithelium and in the co-occurring adenocarcinoma. Digital texture analysis (karyometry) was carried out on hematoxylin and eosin-stained sections from 24 radical prostatectomy specimens with high-grade PIN (12 with flat and 12 with cribriform architectural pattern, respectively) and cancer. Quantification was also conducted on the normal looking secretory epithelium. Discriminant analysis and the nonsupervised learning algorithm P-index were used to identify suitable subsets of features useful for the discrimination and classification of pathological groups and to explore multivariate data structure in the pathological subgroups. The average nuclear abnormality increases monotonically from the histologically normal appearing secretory epithelium to high-grade PIN and to adenocarcinoma. The nuclei from the so-called perimeter compartment of the flat high-grade PIN lesions show a higher nuclear abnormality compared to the nuclei of the cribriform high-grade PINs. Discriminant analysis shows that flat and cribriform high-grade PINs fall into two populations. Processing by the nonsupervised learning algorithm P-index revealed the existence of three well-defined, distinct subpopulations of nuclei of different chromatin phenotype. In the flat high-grade PIN lesions the proportions of nuclei in the three subpopulations are 16.5% (low abnormality), 25.0% (mid abnormality) and 58.5% (high abnormality), respectively. In the cribriform high-grade PIN lesions, 100% of the nuclei are in the mid-abnormality subpopulation. These differences are also discernible in the co-occurring adenocarcinoma and the histologically normal appearing secretory epithelium. To conclude, karyometry and statistical analysis detect the existence of distinct cell subpopulations of different chromatin packaging and phenotype, with the nuclei from the flat high-grade PIN lesions, adjacent normal looking epithelium and co-occurring adenocarcinoma expressing a greater nuclear abnormality than in the specimens with cribriform high-grade PIN.

Prostatic Intraepithelial Neoplasia: An Update

High-grade prostatic intraepithelial neoplasia (HGPIN) is commonly encountered on prostate needle biopsies and, based on epidemiologic, molecular, and animal models, has proven to be the most significant risk factor for prostate cancer and likely represents the premalignant phase of prostatic adenocarcinoma. This lesion is characterized by cellular proliferations within pre-existing ducts and glands, with nuclear and nucleolar enlargement similar to prostate cancer. However, unlike cancer, HGPIN retains a basal cell layer identifiable by immunohistochemistry with the basal cell-specific antibody cytokeratin 34bE12. The incidence of HGPIN identified in needle biopsies is as high as 25%, increases with age, and coexists with prostate cancer in approximately 85% of cases. There appears to be no causal relationship between HGPIN and serum prostate-specific antigen (total, percent free, or density) or radiographic characteristics on transrectal ultrasound. In a large series, the identification of HGPIN on initial needle biopsy is associated with about a 35% risk of prostate cancer on subsequent biopsies. Thus, the finding of HGPIN on prostate needle biopsy necessitates a second biopsy in a patient eligible for curative treatment. As a precursor lesion, HGPIN is currently a target for chemopreventive strategies, including antiandrogens and nutritional supplementation.

High-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (PIN) is now accepted as the most likely preinvasive stage of adenocarcinoma, almost two decades after its first formal description. PIN has a high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent invasive carcinoma. The only method of detection is biopsy; PIN does not significantly elevate serum prostate-specific antigen (PSA) concentration or its derivatives and cannot be detected by current imaging techniques, including ultrasound. Most patients with PIN will develop carcinoma within 10 years. PIN is associated with progressive abnormalities of phenotype and genotype, which are similar to cancer rather than normal prostatic epithelium, indicating impairment of cell differentiation with advancing stages of prostatic carcinogenesis. Androgen deprivation therapy decreases the prevalence and extent of PIN, suggesting that this form of treatment may play a role in chemoprevention.

Chemoprevention of carcinoma prostate: a review

PURPOSE

Chemoprevention of prostate cancer is the administration of agents to prevent, inhibit, or delay progression of prostate cancer. Opportunities exist for testing various types of chemopreventive interventsion.

MATERIAL AND METHODS

The authors reviewed the relevant articles published in the last twenty years and studied the biology of the prostate cancer. An attempt is made to identify intermediate markers and surrogate endpoint markers. The various interventions and initial clinical trial results are described. End points for evaluation are mainly based on changes in PSA, changes of histological precursors, or time of onset of clinical disease.

RESULTS

Nutritional factors such as reduced fat intake, vitamin A, vitamin E, vitamin C, vitamin D, Lycopene and selenium may have a protective effect against prostate cancer.

CONCLUSION

Numerous studies implicate dietary and nutritional factors in the onset and progression of prostate cancer. Hence, it is possible that bioactive compounds (anti-oxidants) like vits. A, C, D, E, minerals like selenium and carotenoids like lycopene can be a part of chemopreventive strategies for prostate cancer. Ongoing studies on nutrition and prostate cancer may bring the required evidence to support what is still only a hypothesis at present. However, absolute recommendation will have to await the results of long term prospective clinical trials.

Inflammatory atrophy of the prostate. Prevalence and significance

CONTEXT

Recently, prostatic atrophy associated with chronic inflammation has been linked to carcinoma either directly or indirectly by first developing into high-grade prostatic intraepithelial neoplasia.

OBJECTIVE

The purpose of our study was to test this hypothesis in autopsies.

DESIGN

A step section method was used to cut the posterior lobe in coronal planes at intervals of 0.3 to 0.5 cm in 100 consecutive autopsies of men older than 40 years. Prostatic atrophy was classified as simple, hyperplastic (or postatrophic hyperplasia), and sclerotic and was analyzed for the presence of chronic inflammation. Prostatic atrophy without (group A) and with inflammation (group B) was correlated with the following variables: age, race, histologic (incidental) carcinoma, high-grade prostatic intraepithelial neoplasia, and extent of both these lesions.

RESULTS

Of the 100 prostates examined, 12%, 22% and 66%, respectively, had no atrophy, atrophy without inflammation (group A), and atrophy with inflammation (group B). There was no statistically significant difference between groups A and B for age (P =.55), race (P =.89), presence of histologic (incidental) carcinoma (P =.89), extensive carcinoma (P =.43), presence of high-grade prostatic intraepithelial neoplasia (P =.65), extensive high-grade intraepithelial neoplasia (P =.30), or subtypes of prostatic atrophy. Neither a topographical relation nor a morphologic transition was seen between prostatic atrophy and histologic carcinoma or high-grade intraepithelial neoplasia. Sclerotic atrophy either alone or combined with other subtypes was more frequent in the group with inflammation. A striking morphologic finding was a topographical relation of focal inflammation with sclerotic atrophy in areas with erosion of the epithelium.

CONCLUSIONS

Inflammatory prostatic atrophy does not appear to be associated with histologic (incidental) carcinoma or high-grade intraepithelial neoplasia. One possible cause of inflammatory infiltrate associated with prostatic atrophy may be the extravasated prostatic secretions, which were noted in areas of eroded epithelium, a common finding in the sclerotic type of prostatic atrophy.

Contemporary pathology of prostate cancer

In less than 20 years since the introduction of serum PSA and the spring-loaded 18-gauge prostatic biopsy needle, pathologists have adjusted to the limited tissue requirements of narrow needle specimens to apply criteria for diagnosis and grading of prostate cancer, borrowing from lessons learned from radical prostatectomies. Substantial gains have been made during this period in the understanding of precancerous lesions, mimics of malignancy, the criteria for minimal cancer, variants of cancer, and treatment-induced changes. The light microscopic findings remain the criterion standard for diagnosis against which all new techniques should be measured. Numerous findings have proven to be of value, including simple quantitation of histopathologic features, cancer volume, perineural invasion, and others.

Prevalence of prostate cancer and prostatic intraepithelial neoplasia in Caucasian Mediterranean males: an autopsy study

BACKGROUND

The prevalence of carcinoma of the prostate gland (CaP) and high-grade prostatic intraepithelial neoplasia (HGPIN) was assessed in a Spanish population, representative of the Caucasian Mediterranean (CM) ethnic group. Data were compared with those described in populations from other geographical regions and in other ethnic groups.

METHODS

CaP and HGPIN were evaluated in a consecutive series of prostatic glands collected at the post-mortem examination of 162 male patients born and living in Spain, aged 20-80 years, and dying from trauma. The glands were sliced every 2-3 mm. All slices were paraffin embedded and sectioned to obtain 5 microm whole-mount sections. To compare the prevalence rate in our series and in other Caucasian populations with that from other geographical areas and other ethnic groups, we used data from the autopsy study performed at the Wayne State University.

RESULTS

Prevalence of CaP is 3.58, 8.82, 14.28, 23.80, 31.7, and 33.33% in the 3rd, 4th, 5th, 6th, 7th, and 8th decades, respectively. The rates of HGPIN were 7.14, 11.75, 35.71, 38.06, 45.40, and 48.15% at the 3rd, 4th, 5th, and 8th decades of life. Both CaP and HGPIN are located preferentially at the peripheral zone of the gland and in 21/27 cases (77.7%), an association between CaP and HGPIN was found. The prevalence of both lesions in CM males is significantly lower than in Caucasian American (CA) and Afro-American (AA) males in all the age groups evaluated.

CONCLUSIONS

Microscopic foci of CaP and HGPIN can be documented in CM males from the 3rd decade of life onwards. The lesions become more frequent and extensive as age increases. The prevalence of both lesions seems to be significantly lower in the CM population than in CA and AA males in all the age groups evaluated.

Distribution of inflammation, pre-malignant lesions, incidental carcinoma in histologically confirmed benign prostatic hyperplasia: a retrospective analysis

OBJECTIVES

We analyze our experience on BPH through 20 years of histopathological examinations performed by the same pathologist.

METHODS

We retrospectively reviewed all histopathological examinations performed from January 1979 to December 1998 in patients undergoing surgery in our urological clinic who were diagnosed with BPH. We limited our evaluation to the following variables in each BPH case analyzed: inflammatory aspects associated with BPH, presence of focal acinar atrophy, atypical adenomatous hyperplasia (AAH), prostatic intraepithelial neoplasia (PIN), incidental prostate carcinoma (IC). These histological variables were analyzed according to some clinical parameters such as age, prostate volume and serum PSA.

RESULTS

The study population was comprised of 3942 cases with histological diagnosis of BPH. The mean patient age was 68.85+/-7.67 years. In particular, inflammatory aspects were associated with BPH in a high percentage of cases (43.1% =1700 cases), predominantly as chronic inflammation. Observation of focal acinar atrophy significantly increased according to patient decade of age (p=0.027). There was a significant trend to increase with age decades (p=0.036) for high grade PIN. A significant difference was found in IC (T1a, T1b) distribution in the different decades of age and especially in regards to both T1a and T1b tumors, there was a trend to increase with patient age (p=0.020 and p=0.025, respectively). On the contrary, the distribution of inflammatory aspects (p<0.001) and AAH (p=0.003) significantly varied according to prostate volume, and particularly in regards to chronic inflammation, there was a trend to increase depending on the prostate volume (p=0.002). Only the presence of T1b tumor but not of the other histological parameters associated to BPH, was able to significantly influence serum PSA.

CONCLUSION

In our analysis different histological variables associated to BPH are differently influenced by the age of patients and prostate volume, and they differently influence serum PSA levels.

Prostatic intraepithelial neoplasia in genetically engineered mice

Several mouse models of human prostate cancer were studied to identify and characterize potential precursor lesions containing foci of atypical epithelial cells. These lesions exhibit a sequence of changes suggesting progressive evolution toward malignancy. Based on these observations, a grading system is proposed to classify prostatic intraepithelial neoplasia (PIN) in genetically engineered mice (GEM). Four grades of GEM PIN are proposed based on their architecture, differentiation pattern, and degree of cytological atypia. PIN I lesions have one or two layers of atypical cells. PIN II has two or more layers of atypical cells. PIN III has large, pleomorphic nuclei with prominent nucleoli and the cells tend to involve the entire lumen with expansion of the duct outlines. PIN IV lesions contain atypical cells that fill the lumen and bulge focally into, and frequently compromise, the fibromuscular sheath. Within the same cohorts, the lower grade PINs first appear earlier than the higher grades. Morphometric and immunohistochemical analyses confirm progressive change. Although the malignant potential of PIN IV in mice has not been proven, GEM PIN is similar to human PIN. This PIN classification system is a first step toward a systematic evaluation of the biological potential of these lesions in GEM.

Precancerous lesions and conditions of the prostate: from morphological and biological characterization to chemoprevention

Prostatic intraepithelial neoplasia (PIN) is composed of dysplastic cells with a luminal cell phenotype, expressing the androgen receptor as well as prostate-specific antigen. PIN is characterized by progressive abnormalities of phenotype that are intermediate between normal prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of carcinogenesis. High-grade PIN is considered the most likely precursor of prostatic carcinoma, according to virtually all available evidence. Androgen deprivation decreases the prevalence and extent of PIN and the degree of capillary vascularization (e.g., angiogenesis) in the surrounding stroma via suppression of vascular endothelial growth factor production. Prostatic carcinoma is also likely to arise from precursor lesions other than high-grade PIN such as low-grade PIN, atypical adenomatous hyperplasia, malignancy-associated foci, and atrophy.

Effect of androgen deprivation therapy on prostatic intraepithelial neoplasia

There is a marked decrease in the prevalence and extent of high-grade prostatic intraepithelial neoplasia (PIN) in men with prostate cancer after androgen deprivation therapy (ADT) when compared with untreated cases. Basal cell hyperplasia, cytoplasmic clearing, and prominent atrophy of benign acini, with decreased ratio of acini to stroma, accompany this decrease. These findings indicate that the benign and dysplastic prostatic epithelium is androgen dependent. In the normal prostatic epithelium, luminal secretory cells are more sensitive to the absence of androgen than basal cells, and the proliferative cells of high-grade PIN share this androgen sensitivity. The loss of some normal, hyperplastic, and dysplastic epithelial cells with ADT is probably because of acceleration of programmed single-cell death. Remarkably little is known about the comparative effect of different forms of chemical ADT on PIN and cancer, although there appears to be a limited and consistent repertoire of morphologic responses to all forms of this therapy. Conversely, blockade of 5alpha-reductase with finasteride has little or no effect on PIN (or benign epithelium and cancer), unlike other forms of ADT. A recent international consensus conference sponsored by the World Health Organization concluded that identification of high-grade PIN offered the possibility of chemoprevention with hormonal therapy to block the development of clinical cancer. Multiple chemoprevention trials are planned or under way to address this hypothesis.

Karyometry of secretory cell nuclei in high-grade PIN lesions

BACKGROUND

The goal of this study was a karyometric characterization of secretory cell nuclei in high-grade prostatic intraepithelial neoplasia (PIN) lesions. Specifically, the hypothesis is tested that distinctly different subgroups of nuclei exist in these lesions.

METHODS

High-resolution images of 1,713 nuclei from high-grade PIN lesions were recorded. Karyometric features were computed. Discriminant function scores against normal reference nuclei, and nuclear abnormality values were derived. Data sets were processed by a nonsupervised learning algorithm to establish the presence of subgroups of nuclei with statistically different nuclear chromatin distributions.

RESULTS

Three sets of nuclei were formed, facing an intact basal cell layer, a near vanishing basal cell layer, and a gap in the basal cell layer. For each set, a nonsupervised learning algorithm formed three statistically different subgroups of approximately equal sizes. Each subgroup is found in every one of the three sampling locations. The total optical density distribution of nuclei in two subgroups suggests an aneuploid distribution, the third subgroup has a near diploid distribution.

CONCLUSIONS

Secretory cell nuclei in high-grade PIN lesions are a heterogeneous population, forming statistically different subgroups. Studies aimed at characterizing the progression of such lesions should consider the inhomogeneous nature of these nuclei.