Pitfalls in the diagnosis of prostatic cancer: retrospective review of 1791 cases with clinical outcome

Prostate sclerosing adenopathy: A clinicopathological and immunohistochemical study of twelve patients

BACKGROUND

Although sclerosing adenopathy of the prostate is a very rare benign disease, an effective differential diagnosis is required. Here, we report the clinicopathological and immunohistochemical morphological features of 12 cases of sclerosing adenopathy of the prostate to improve understanding of the disease.

AIM

To investigate the clinicopathological features, diagnosis, and immunohistochemical phenotypes that distinguish prostate sclerosing adenopathy from other conditions.

METHODS

The clinical data, laboratory tests, pathological morphology, and immunohistochemical phenotypes of 12 cases of prostatic sclerosing adenopathy were retrospectively analyzed, and the relevant literature was reviewed.

RESULTS

All patients were elderly men (mean age, 71.7 years; 62–83 years). Eleven of them had hematuria, urinary frequency, urinary urgency, difficulty in urination, and serum total prostate-specific antigen values within the normal range. One patient had increased blood pressure. Enlarged prostates with single to multiple calcifying foci were observed. Moreover, prostate tissue hyperplastic changes were observed in all patients. Small follicular hyperplastic nodules without an obvious envelope, with a growth pattern mimicking the infiltration pattern of "prostate adenocarcinoma" were noted. Basal cells expressed AR, CKH, P63, and CK5/6, and myoepithelial markers, such as calponin, S100, and smooth muscle actin. No recurrence or exacerbation of the lesions was observed, except for one case of death due to bladder cancer.

CONCLUSION

Prostatic sclerosing adenopathy is highly misdiagnosed as prostate adenocarcinoma or other tumor-like lesions. Therefore, it should attract the attention of clinicopathologic researchers.

Three-dimensional architecture of common benign and precancerous prostate epithelial lesions

Aims

Many glandular lesions can mimic prostate cancer microscopically, including atrophic glands, adenosis and prostatic intraepithelial neoplasia. While the characteristic histopathological and immunohistochemical features of these lesions have been well established, little is known about their three‐dimensional architecture. Our objective was to evaluate the three‐dimensional organisation of common prostate epithelial lesions.

Methods and results

500 μm‐thick punches (n = 42) were taken from radical prostatectomy specimens, and stained with antibodies targeting keratin 8–18 and keratin 5 for identification of luminal and basal cells, respectively. Tissue samples were optically cleared in benzyl alcohol:benzyl benzoate and imaged using a confocal laser scanning microscope. The three‐dimensional architecture of peripheral and transition zone glands was acinar, composed of interconnecting and blind‐ending saccular tubules. In simple atrophy, partial atrophy and post‐atrophic hyperplasia, the acinar structure was attenuated with branching blind‐ending tubules from parental tubular structures. Three‐dimensional imaging revealed a novel variant of prostate atrophy characterised by large Golgi‐like atrophic spaces parallel to the prostate surface, which were represented by thin, elongated tubular structures on haematoxylin and eosin (H&E) slides. Conversely, adenosis lacked acinar organisation, so that it closely mimicked low‐grade prostate cancer. High‐grade prostatic intraepithelial neoplasia displayed prominent papillary intraluminal protrusions but retained an acinar organisation, whereas intraductal carcinoma predominantly consisted of cribriform proliferations with either spheroid, ellipsoid or complex interconnecting lumens.

Conclusions

While various prostate epithelial lesions might mimic malignancy on H&E slides, their three‐dimensional architecture is acinar and clearly different from the tubular structure of prostate cancer, with adenosis as an exception.

Histopathologic False-positive Diagnoses of Prostate Cancer in the Age of Immunohistochemistry

There are few studies into the rate and causes of histopathologic false-positive diagnosis of prostate cancer. Only 2 of these, including a previous one from our group, incorporate survival data. In addition, in none of the previous studies had immunohistochemistry (IHC) been originally requested on any of the misdiagnosed cases. Diagnostic biopsies (n=1080) and transurethral resection of prostate specimens (n=314) from 1394 men with clinically localized prostate cancer diagnosed in the United Kingdom but treated conservatively between 1990 and 2003 were reviewed by a panel of 3 genitourinary pathologists. Thirty-five cases were excluded for being potentially incomplete. Of the remaining 1359, 30 (2.2%) were reassigned to a nonmalignant category (26 benign and 4 suspicious for malignancy). IHC had been originally performed on 7 of these. The reasons for the errors were recorded on each case: adenosis (19), partial atrophy (3), prostatic intraepithelial neoplasia (2), seminal vesicle epithelium (1), and hyperplasia (1). Follow-up of these men revealed only one prostate cancer-related death, possibly due to unsampled tumor. In conclusion, a relatively small number of prostate cancer mimics were responsible for a large proportion of the false-positive prostate cancer diagnoses and the use of IHC did not prevent the overcall of benign entities as cancer in approximately a quarter of these cases. Targeting these mimics at educational events and raising awareness of the pitfalls in the interpretation of IHC in prostate cancer diagnosis, emphasizing that glands within a suspicious focus should be treated as a whole rather than individually, may be beneficial in lowering the rate of false-positive diagnosis.

Validation of a contemporary prostate cancer grading system using prostate cancer death as outcome

BACKGROUND

Gleason scoring (GS) has major deficiencies and a novel system of five grade groups (GS⩽6; 3+4; 4+3; 8; ⩾9) has been recently agreed and included in the WHO 2016 classification. Although verified in radical prostatectomies using PSA relapse for outcome, it has not been validated using prostate cancer death as an outcome in biopsy series. There is debate whether an 'overall' or 'worst' GS in biopsies series should be used.

METHODS

Nine hundred and eighty-eight prostate cancer biopsy cases were identified between 1990 and 2003, and treated conservatively. Diagnosis and grade was assigned to each core as well as an overall grade. Follow-up for prostate cancer death was until 31 December 2012. A log-rank test assessed univariable differences between the five grade groups based on overall and worst grade seen, and using univariable and multivariable Cox proportional hazards. Regression was used to quantify differences in outcome.

RESULTS

Using both 'worst' and 'overall' GS yielded highly significant results on univariate and multivariate analysis with overall GS slightly but insignificantly outperforming worst GS. There was a strong correlation with the five grade groups and prostate cancer death.

CONCLUSIONS

This is the largest conservatively treated prostate cancer cohort with long-term follow-up and contemporary assessment of grade. It validates the formation of five grade groups and suggests that the 'worst' grade is a valid prognostic measure.

Interpretive Diagnostic Error Reduction in Surgical Pathology and Cytology: Guideline From the College of American Pathologists Pathology and Laboratory Quality Center and the Association of Directors of Anatomic and Surgical Pathology

CONTEXT

Additional reviews of diagnostic surgical and cytology cases have been shown to detect diagnostic discrepancies.

OBJECTIVE

To develop, through a systematic review of the literature, recommendations for the review of pathology cases to detect or prevent interpretive diagnostic errors.

DESIGN

The College of American Pathologists Pathology and Laboratory Quality Center in association with the Association of Directors of Anatomic and Surgical Pathology convened an expert panel to develop an evidence-based guideline to help define the role of case reviews in surgical pathology and cytology. A literature search was conducted to gather data on the review of cases in surgical pathology and cytology.

RESULTS

The panel drafted 5 recommendations, with strong agreement from open comment period participants ranging from 87% to 93%. The recommendations are: (1) anatomic pathologists should develop procedures for the review of selected pathology cases to detect disagreements and potential interpretive errors; (2) anatomic pathologists should perform case reviews in a timely manner to avoid having a negative impact on patient care; (3) anatomic pathologists should have documented case review procedures that are relevant to their practice setting; (4) anatomic pathologists should continuously monitor and document the results of case reviews; and (5) if pathology case reviews show poor agreement within a defined case type, anatomic pathologists should take steps to improve agreement.

CONCLUSIONS

Evidence exists that case reviews detect errors; therefore, the expert panel recommends that anatomic pathologists develop procedures for the review of pathology cases to detect disagreements and potential interpretive errors, in order to improve the quality of patient care.

The spectrum of morphology in non-neoplastic prostate including cancer mimics

The spectrum of morphology in non-neoplastic prostate includes lesions of prostatic epithelial origin, the most common being atrophy, including partial atrophy, adenosis (atypical adenomatous hyperplasia), basal cell hyperplasia and crowded benign glands, as well as those of non-prostatic origin, such as seminal vesicle epithelium. These lesions often mimic lower-grade prostatic adenocarcinoma whereas others, such as granulomatous prostatitis, for example, are in the differential diagnosis of adenocarcinoma, Gleason grades 4 or 5. Diagnostic awareness of the salient histomorphological and relevant immunohistochemical features of these prostatic pseudoneoplasms is critical to avoid rendering false positive diagnoses of malignancy.

Pathology in prostate research: optimizing the pathological data

Pathology remains the gold standard for the diagnosis and local staging and grading of prostate cancer. However, as in any discipline, there are variations in national standards and protocols leading to possible significant intra-observer variations. This can significantly impact on the data supplied to clinical trials. Diagnostic and grading criteria. Error rates in the diagnosis of prostate cancer have improved but the possibility that diagnostic error may be discovered has to be addressed in any research series. Major changes in Gleason grading have occurred in the past 40 years and this may lead to suboptimal application of grades in research cohorts, falsely raising the prognostic power of new biomarkers. Tumor measurements and staging criteria. Further information that may provide additional prognostic information include various measures of tumor extent and peri-neural invasion in biopsy specimens. Standardization of measures of tumor extent is necessary to give more useful assessments of prognosis. In radical prostatectomy specimens there are a number of other staging measurements which might be applied, including tumor volume, margin status, extra-capsular extension and nodal positivity though many of these variables are interdependent. Conclusion. Appropriate utilization of such pathological material will produce improved cohorts in which it will be possible to test new biomarkers with increased rigor.

Multimodal microscopy for automated histologic analysis of prostate cancer

Background

Prostate cancer is the single most prevalent cancer in US men whose gold standard of diagnosis is histologic assessment of biopsies. Manual assessment of stained tissue of all biopsies limits speed and accuracy in clinical practice and research of prostate cancer diagnosis. We sought to develop a fully-automated multimodal microscopy method to distinguish cancerous from non-cancerous tissue samples.

Methods

We recorded chemical data from an unstained tissue microarray (TMA) using Fourier transform infrared (FT-IR) spectroscopic imaging. Using pattern recognition, we identified epithelial cells without user input. We fused the cell type information with the corresponding stained images commonly used in clinical practice. Extracted morphological features, optimized by two-stage feature selection method using a minimum-redundancy-maximal-relevance (mRMR) criterion and sequential floating forward selection (SFFS), were applied to classify tissue samples as cancer or non-cancer.

Results

We achieved high accuracy (area under ROC curve (AUC) >0.97) in cross-validations on each of two data sets that were stained under different conditions. When the classifier was trained on one data set and tested on the other data set, an AUC value of ~0.95 was observed. In the absence of IR data, the performance of the same classification system dropped for both data sets and between data sets.

Conclusions

We were able to achieve very effective fusion of the information from two different images that provide very different types of data with different characteristics. The method is entirely transparent to a user and does not involve any adjustment or decision-making based on spectral data. By combining the IR and optical data, we achieved high accurate classification.

Hsp-27 expression at diagnosis predicts poor clinical outcome in prostate cancer independent of ETS-gene rearrangement

BACKGROUND

This study was performed to test the hypothesis that expression of small heat shock protein Hsp-27 is, at diagnosis, a reliable predictive biomarker of clinically aggressive prostate cancer.

METHODS

A panel of tissue microarrays constructed from a well-characterised cohort of 553 men with conservatively managed prostate cancer was stained immunohistochemically to detect Hsp-27 protein. Hsp-27 expression was compared with a series of pathological and clinical parameters, including outcome.

RESULTS

Hsp-27 staining was indicative of higher Gleason score (P<0.001). In tissue cores having a Gleason score >7, the presence of Hsp-27 retained its power to independently predict poor clinical outcome (P<0.002). Higher levels of Hsp-27 staining were almost entirely restricted to cancers lacking ERG rearrangements (chi2 trend=31.4, P<0.001), although this distribution did not have prognostic significance.

INTERPRETATION

This study has confirmed that, in prostate cancers managed conservatively over a period of more than 15 years, expression of Hsp-27 is an accurate and independent predictive biomarker of aggressive disease with poor clinical outcome (P<0.001). These findings suggest that apoptotic and cell-migration pathways modulated by Hsp-27 may contain targets susceptible to the development of biologically appropriate chemotherapeutic agents that are likely to prove effective in treating aggressive prostate cancers.

Fractal analysis of two-dimensional vascularity in primary prostate cancer and surrounding non-tumoral parenchyma

Prostate cancer is the fifth most frequent cancer in the world. However, none of the actual prognostic factors provide a valid index for predicting patient outcome. Here, we evaluate the two-dimensional vascularity in primary prostate tumors and surrounding non-tumoral parenchyma by means of fractal geometry, and assess any correlations between the results and some clinical and pathological parameters of prostate carcinoma. Prostate sections from 27 carcinoma patients were treated with CD34 antibodies. Two >10mm(2) areas of tumoral and surrounding non-tumoral parenchyma were digitized using an image analysis system that automatically quantified the fractal dimension of the vascular surface. Data were correlated with patient's age, PSA level, clinical and pathological stage, Gleason score, tumor volume, vascular invasion, surgical margins, and biochemical relapse. Two groups of patients were distinguished on the basis of whether the fractal dimension of their tumoral vascular surface was higher (group 1) or lower (group 2) than that of the surrounding non-tumoral parenchyma. Statistically significant between-group differences were found in terms of serum PSA levels (p=0.0061), tumor volume (p=0.0017), and biochemical relapse (p=0.031). The patients in group 2 had a poorer outcome. Our findings suggest a group of prostate cancer patients with a poor outcome, and the vascular surface fractal dimension as a helpful geometrical index in clinical practice.

Prostate cancer in male BRCA1 and BRCA2 mutation carriers has a more aggressive phenotype

There is a high and rising prevalence of prostate cancer (PRCA) within the male population of the United Kingdom. Although the relative risk of PRCA is higher in male BRCA2 and BRCA1 mutation carriers, the histological characteristics of this malignancy in these groups have not been clearly defined. We present the histopathological findings in the first UK series of BRCA1 and BRCA2 mutation carriers with PRCA. The archived histopathological tissue sections of 20 BRCA1/2 mutation carriers with PRCA were collected from histopathology laboratories in England, Ireland and Scotland. The cases were matched to a control group by age, stage and serum PSA level of PRCA cases diagnosed in the general population. Following histopathological evaluation and re-grading according to current conventional criteria, Gleason scores of PRCA developed by BRCA1/2 mutation carriers were identified to be significantly higher (Gleason scores 8, 9 or 10, P=0.012) than those in the control group. Since BRCA1/2 mutation carrier status is associated with more aggressive disease, it is a prognostic factor for PRCA outcome. Targeting screening to this population may detect disease at an earlier clinical stage which may therefore be beneficial.