Morphologic criteria for the diagnosis of prostatic adenocarcinoma in needle biopsy specimens. A study of 250 consecutive cases in a routine surgical pathology practice

Activation of neural lineage networks and ARHGEF2 in enzalutamide-resistant and neuroendocrine prostate cancer and association with patient outcomes

Background

Treatment-emergent neuroendocrine prostate cancer (NEPC) after androgen receptor (AR) targeted therapies is an aggressive variant of prostate cancer with an unfavorable prognosis. The underlying mechanisms for early neuroendocrine differentiation are poorly defined and diagnostic and prognostic biomarkers are needed.

Methods

We performed transcriptomic analysis on the enzalutamide-resistant prostate cancer cell line C4-2B MDVR and NEPC patient databases to identify neural lineage signature (NLS) genes. Correlation of NLS genes with clinicopathologic features was determined. Cell viability was determined in C4-2B MDVR and H660 cells after knocking down ARHGEF2 using siRNA. Organoid viability of patient-derived xenografts was measured after knocking down ARHGEF2.

Results

We identify a 95-gene NLS representing the molecular landscape of neural precursor cell proliferation, embryonic stem cell pluripotency, and neural stem cell differentiation, which may indicate an early or intermediate stage of neuroendocrine differentiation. These NLS genes positively correlate with conventional neuroendocrine markers such as chromogranin and synaptophysin, and negatively correlate with AR and AR target genes in advanced prostate cancer. Differentially expressed NLS genes stratify small-cell NEPC from prostate adenocarcinoma, which are closely associated with clinicopathologic features such as Gleason Score and metastasis status. Higher ARGHEF2, LHX2, and EPHB2 levels among the 95 NLS genes correlate with a shortened survival time in NEPC patients. Furthermore, downregulation of ARHGEF2 gene expression suppresses cell viability and markers of neuroendocrine differentiation in enzalutamide-resistant and neuroendocrine cells.

Conclusions

The 95 neural lineage gene signatures capture an early molecular shift toward neuroendocrine differentiation, which could stratify advanced prostate cancer patients to optimize clinical treatment and serve as a source of potential therapeutic targets in advanced prostate cancer.

Intraductal Carcinoma of the Prostate: Extreme Nuclear Size Is Not a Diagnostic Parameter

High-grade prostatic adenocarcinoma involving duct/acinar structures is labeled intraductal carcinoma of the prostate (IDCP). As numerous studies have shown that IDCP is associated with high stage disease with a significant negative impact on cancer-specific survival, accurate diagnosis is crucial to ensure appropriate patient management. The definition of IDCP recommended by 2016 World Health Organization (WHO) classification suggests that cases of IDCP with micropapillary or loose cribriform architecture without comedonecrosis should have cells with ≥6× nuclear enlargement. It is unclear how this size criterion was derived and which of the parameters of nuclear size (nuclear diameter, nuclear surface area, or nuclear perimeter) it relates to. To evaluate the extent of nuclear enlargement in IDCP, we performed morphometric analyses relating to each of these parameters in 100 radical prostatectomy specimens. One hundred nuclei from foci of IDCP and 50 nuclei from foci of normal luminal epithelium were examined for each patient. Diagnosis of IDCP was based on cells with definite features of carcinoma present within duct/acinar structures. Comparing the means of each of the parameters between IDCP cells and benign luminal cells, there was a statistically significant enlargement in nuclear perimeter (P<0.0005), nuclear area (P<0.0005), and nuclear diameter (P<0.0005); however, the difference in mean nuclear size was limited to factors of 1.3×, 1.6×, and 1.3×, respectively. Three patients each had rare large nuclei (largest perimeter 45, 45, and 44 μm; maximum nuclear area 135, 136, and 136 μm2; and the largest diameter 18 µm in each). For these rare cells, the nuclear size difference, when compared with benign nuclei was; nuclear perimeter 2.0×, 2.1×, and 2.1×; nuclear area 3.6×, 3.8×, and 3.8×; and nuclear maximum diameter 3.0×, 2.5×, and 2.5×. The definition of nuclear enlargement of ≥6× was not reached in any of our cases, all of which clearly showed features of duct invasive carcinoma. In these cases, reliance on nuclear size criteria would have resulted in underdiagnosis of IDCP. This is of concern as failure to recognize IDCP, particularly in needle biopsies, could lead to delays in the timely treatment of aggressive high-grade prostate cancer, resulting in cancer progression and suboptimal patient oncological outcomes.

Neuroendocrine and Aggressive-Variant Prostate Cancer

In prostate cancer, neuroendocrine (NE) differentiation may rarely present de novo or more frequently arises following hormonal therapy in patients with castration-resistant prostate cancer (CRPC). Its distinct phenotype is characterized by an aggressive clinical course, lack of responsiveness to hormonal therapies and poor prognosis. Importantly, a subset of CRPC patients exhibits an aggressive-variant disease with very similar clinical and molecular characteristics to small-cell prostate cancer (SCPC) even though tumors do not have NE differentiation. This aggressive-variant prostate cancer (AVPC) also shares the sensitivity of SCPC to platinum-based chemotherapy albeit with short-lived clinical benefit. As optimal treatment strategies for AVPC remain elusive, currently ongoing research efforts aim to enhance our understanding of the biology of this disease entity and improve treatment outcomes for our patients. This review is an overview of our current knowledge on prostate cancer with NE differentiation and AVPC, with a focus on their clinical characteristics and management, including available as well as experimental therapeutic strategies.

Comparison of Immunohistochemistry Expression of CK7, HMWK and PSA in High-Grade Prostatic Adenocarcinoma and Bladder Transitional Cell Carcinoma

Background & Objective:

Prostate adenocarcinoma is the most common malignancy in males, and the urothelial bladder carcinoma is also prevalent. The histological characteristic of these two tumors is very similar in high-grade cases, and their differentiation is difficult. This study was performed to compare the immunohistochemistry panel of high-grade prostate adenocarcinomas and high-grade urothelial bladder carcinomas.

Methods:

In this cross-sectional study, 36 cases of prostate adenocarcinoma and 36 urothelial bladder carcinoma samples were collected from the pathology department of Shahid Beheshti Hospital in Hamedan. For each sample, expression of Cytokeratin 7, high-molecular-weight cytokeratin and Prostate-specific antigen markers was evaluated by immunohistochemistry. Comparison of expression of these markers in high-grade bladder tumors and prostate tumors was made by SPSS 25 using Chi-square test.

Results:

In this study, the Cytokeratin 7 positivity was seen in 88.9% of bladder cancer versus 27.8% of prostate cancer samples. High-molecular-weight cytokeratin positive immunoreactivity was noted in 55.6% of bladder cancer and 5.6% of prostate cancer samples. Prostate-specific antigen marker showed positive results in 94.4% of prostate cancer samples, but no positivity was evident in those of bladder cancer.

Conclusion:

A panel of immunohistochemical stains can be used to differentiate high-grade prostate adenocarcinoma from urothelial bladder carcinoma in those cases which are challenging to diagnose.

Deep Adversarial Training for Multi-Organ Nuclei Segmentation in Histopathology Images

Nuclei mymargin segmentation is a fundamental task for various computational pathology applications including nuclei morphology analysis, cell type classification, and cancer grading. Deep learning has emerged as a powerful approach to segmenting nuclei but the accuracy of convolutional neural networks (CNNs) depends on the volume and the quality of labeled histopathology data for training. In particular, conventional CNN-based approaches lack structured prediction capabilities, which are required to distinguish overlapping and clumped nuclei. Here, we present an approach to nuclei segmentation that overcomes these challenges by utilizing a conditional generative adversarial network (cGAN) trained with synthetic and real data. We generate a large dataset of H&E training images with perfect nuclei segmentation labels using an unpaired GAN framework. This synthetic data along with real histopathology data from six different organs are used to train a conditional GAN with spectral normalization and gradient penalty for nuclei segmentation. This adversarial regression framework enforces higher-order spacial-consistency when compared to conventional CNN models. We demonstrate that this nuclei segmentation approach generalizes across different organs, sites, patients and disease states, and outperforms conventional approaches, especially in isolating individual and overlapping nuclei.

Clinical presentation of ductal carcinoma in situ of breast with intraluminal crystalloids: Radiologic-histologic correlation

Intraluminal crystalloids have rarely been described in the breast, particularly in cases with ductal carcinoma in situ (DCIS). We recently encountered a case of DCIS of the breast associated with numerous intraluminal crystalloids. The patient presented with a mass in the right breast, and microcalcifications were detected on screening and diagnostic mammograms; the patient underwent needle biopsies, lumpectomy, and skin-sparing mastectomy. Invasive ductal carcinoma associated with extensive DCIS was diagnosed. Multiple refractile, eosinophilic crystalloids, with variable morphologies including rectangular, triangular and needle-like with sharp borders, were observed within the lumina of DCIS, besides calcium phosphate microcalcifications. We report this case together with a literature review on crystalloid-containing lesions in breast and non-breast tissues. We also studied radiologic findings of these crystalloids using a specimen radiograph.

Prostate cancer: diagnostic criteria and role of immunohistochemistry

The diagnosis of prostate cancer is based on microscopic criteria. Presently, prostate needle biopsy interpretation can be a challenge for the pathologist due to the increased number of specimens with limited amount of suspicious glands and minimal atypia. It is critical for the pathologist to have an organized methodical approach when considering the morphological features enabling a definitive diagnosis of prostate cancer. Although several diagnostic criteria and supportive features have been advocated, only few findings are absolutely specific and diagnostic of prostate cancer. The diagnosis of prostate cancer relies on a combination of architectural and cytological features that are reviewed in detail herein. Infiltrative growth pattern, prominent nucleoli and lack of basal cells are the most useful diagnostic criteria. Perineural invasion, glomerulation and mucinous fibroplasia are pathognomonic features of prostate cancer, although uncommon on small prostate cancer foci. The role of immunohistochemistry in establishing a diagnosis of limited prostate is addressed.

Histopathology of Prostate Cancer

This review focuses on histopathological aspects of carcinoma of the prostate. A tissue diagnosis of adenocarcinoma is often essential for establishing a diagnosis of prostate cancer, and the foundation for a tissue diagnosis is currently light microscopic examination of hematoxylin and eosin (H&E)-stained tissue sections. Markers detected by immunohistochemistry on tissue sections can support a diagnosis of adenocarcinoma that is primary in the prostate gland or metastatic. Histological variants of carcinoma of the prostate are important for diagnostic recognition of cancer or as clinicopathologic entities that have prognostic and/or therapeutic significance. Histological grading of adenocarcinoma of the prostate, including use of the 2014 International Society of Urological Pathology (ISUP) modified Gleason grades and the new grade groups, is one of the most powerful prognostic indicators for clinically localized prostate cancer, and is one of the most critical factors in determination of management of these patients.

Typing the atypical: Diagnostic issues and predictive markers in suspicious prostate lesions

As much as 5% of prostate biopsies yield findings equivocal for malignancy even for skilled uropathologist; such "grey zone" lesions have been addressed in many ways, although the acronym ASAP (atypical small acinar proliferation) is the most widely used when referring to an atypical focus suspicious, but not diagnostic, for malignancy. Since the introduction of this diagnostic category more than 20 years ago, debate has ensued over its histological characterization and clinical significance. Pathology reporting of ASAP, commonly based on strict morphological criteria and traditional immunohistochemical markers such as basal cell antibodies, has been improved by recent availability of novel immunohistochemical markers such as AMACR and ERG. Further pathological issues, such as the role of pre-analytical variables, number of tissue levels, interobserver variability, and association with prostatic intraepithelial neoplasia also play a role in the optimal assessment of ASAP. Apart from diagnostic issues, a major issue is ASAP predictive value for prostate cancer on repeat biopsy. Therefore, attempts have been made to identify clinical and biological parameters that could predict subsequent diagnosis of malignancy as well as define time and modality of repeat biopsy. Finally, pathological features of cancers detected after a previous ASAP diagnosis are compared with those diagnosed at first prostate biopsy.

Clinicopathological study of 9 cases of prostate cancer involving the rectal wall

Background

Prostate cancer involving the rectal wall is rare and may lead to diagnostic pitfalls.

Case presentation

Out of 9504 patients with rectal tumors between January 2003 and January 2015, 9 patients (elderly with a mean age of 74 years) with prostate cancer involving the rectal wall were clinically misdiagnosed with rectal cancer. The lesions were located in the rectum, and included 3 circumferential rectal masses, 1 ulceration lesion, 1 crater-like mass, and 4 protruding lesions. Specimens were acquired using biopsy, fine needle aspiration, or resection. The initial symptoms of these patients included rectal urgency, bowel obstruction, and lower gastrointestinal bleeding. Prostate-related symptoms were not obvious. Histologically, 2 cases showed cancer cell invasion in the mucosa, 1 showed transmural invasion from the mucosa to subserosal soft tissues, and 7 cases had submucosa and muscularis propria involvement. All the 9 cases had muscularis propria involvement. However, there were no intraepithelial neoplasias in the mucosal layer, which is reminiscent of rectal carcinoma. The tumors consisted of small-sized or foamy cells that formed acinus-like, duct-like, and cribriform-like structures. We conducted histological staining and an immunohistochemical analysis for CDX-2, prostate-specific antigen (PSA), P504s, villin, carcinoembryonic antigen, CK-pan, cytokeratin 20, and Ki-67. All tumors were PSA and CK-pan positive, 5 of 9 tumors were P504s-positive, and all tumors were negative for the other markers. All patients underwent standard therapy for prostate cancer after the definitive pathological diagnosis. As of March 31, 2015, 8 patients were alive and 1 had died of prostate cancer 6 months posttreatment.

Conclusions

Adenocarcinoma appearing in the rectal wall is not always rectal carcinoma. It is necessary to perform a differential diagnosis for prostate cancer in cases of rectal malignant tumors in elderly male patients. Any treatment should be postponed until the final definitive diagnosis is reached.

Artefact as the Pathologist’s Friend: Peritumoral Retraction in In Situ and Infiltrating Duct Carcinoma of the Breast

Peritumoral retraction artefact appears in tissue sections as an empty space partially or completely encircling a nest of tumor cells, usually in conformity with the rounded or angular outline of that particular nest. The present study was designed to test this finding in a large series of cases and to quantify the appearance of peritumoral retraction artefact in, in situ and infiltrating duct carcinoma of the breast. We examined 199 cases of infiltrating duct carcinoma (IDC) and 188 cases of ductal carcinoma in situ (DCIS). Of the total of 387 cases, 111 were core needle biopsies, whereas the others were larger resections. In each specimen, retraction was evaluated on hematoxylin and eosin-stained slides as negative, 1+ (1% to 25% of tumor showing retraction), 2+ (26% to 50%), 3+ (51% to 75%), or 4+ (76% to 100%). Overall, peritumoral retraction was noted in 168 of 199 cases (84.4%) of IDC, versus 30 of 188 cases (16%) of DCIS ( P < 0.0001). Peritumoral retraction scored as 2+ or greater (26% to 50%) was seen in only 1 of 188 DCIS specimens, compared with 77 of 199 IDC. Thus, peritumoral retraction artefact appears to be a significant finding seen during the evaluation of hematoxylin and eosin specimens for the diagnosis of carcinoma. We discuss the possibility that this phenomenon might represent true prelymphatic space involvement rather than a fixation artefact.

Correlation of Periacinar Retraction Clefting in Needle Core Biopsies and Corresponding Prostatectomy Specimens of Patients with Prostatic Adenocarcinoma

One of the underemphasized supportive criteria for the diagnosis of prostatic cancer is the presence of retraction clefting around neoplastic glands. We analyzed a series of 152 prostatic cancer cases to determine the frequency, extent, and correlation of periacinar retraction clefting between needle core biopsies (NCB) and corresponding matched radical prostatectomy (RP) specimens. Clefting was significantly more frequent in neoplastic compared to nonneoplastic acini in NBC and RP (p<0.05). There was no significant difference in the frequency of retraction clefting in neoplastic acini between NCB and corresponding RP (p>O.05). We have also found a concordance in matched RP and NCB (Kappa=0.582). We conclude that periacinar retraction clefting appears more frequently in neoplastic acini and could serve as a reliable criterion in the diagnosis of prostatic adenocarcinoma.

Semantic interpretation of robust imaging features for Fuhrman grading of renal carcinoma

Pattern recognition in tissue biopsy images can assist in clinical diagnosis and identify relevant image characteristics linked with various biological characteristics. Although previous work suggests several informative imaging features for pattern recognition, there exists a semantic gap between characteristics of these features and pathologists' interpretation of histopathological images. To address this challenge, we develop a clinical decision support system for automated Fuhrman grading of renal carcinoma biopsy images. We extract 1316 color, shape, texture and topology features and develop one vs. all models for four Fuhrman grades. Our models are highly accurate with 90.4% accuracy in a four-class prediction. Predictivity analysis suggests good generalization of the model development methodology through robustness to dataset sampling in cross-validation. We provide a semantic interpretation for the imaging features used in these models by linking features to pathologists' grading criteria. Our study identifies novel imaging features that are semantically linked to Fuhrman grading criteria.

Automated image based prominent nucleoli detection

Introduction:

Nucleolar changes in cancer cells are one of the cytologic features important to the tumor pathologist in cancer assessments of tissue biopsies. However, inter-observer variability and the manual approach to this work hamper the accuracy of the assessment by pathologists. In this paper, we propose a computational method for prominent nucleoli pattern detection.

Materials and Methods:

Thirty-five hematoxylin and eosin stained images were acquired from prostate cancer, breast cancer, renal clear cell cancer and renal papillary cell cancer tissues. Prostate cancer images were used for the development of a computer-based automated prominent nucleoli pattern detector built on a cascade farm. An ensemble of approximately 1000 cascades was constructed by permuting different combinations of classifiers such as support vector machines, eXclusive component analysis, boosting, and logistic regression. The output of cascades was then combined using the RankBoost algorithm. The output of our prominent nucleoli pattern detector is a ranked set of detected image patches of patterns of prominent nucleoli.

Results:

The mean number of detected prominent nucleoli patterns in the top 100 ranked detected objects was 58 in the prostate cancer dataset, 68 in the breast cancer dataset, 86 in the renal clear cell cancer dataset, and 76 in the renal papillary cell cancer dataset. The proposed cascade farm performs twice as good as the use of a single cascade proposed in the seminal paper by Viola and Jones. For comparison, a naive algorithm that randomly chooses a pixel as a nucleoli pattern would detect five correct patterns in the first 100 ranked objects.

Conclusions:

Detection of sparse nucleoli patterns in a large background of highly variable tissue patterns is a difficult challenge our method has overcome. This study developed an accurate prominent nucleoli pattern detector with the potential to be used in the clinical settings.

Prostate cancer stroma: an important factor in cancer growth and progression

Reactive stromal changes that occur in different human cancers might play a role in local tumor spreading and progression. Studies done on various human cancers have shown activated stromal cell phenotypes, modified extracellular matrix (ECM) composition, and increased microvessel density. Furthermore, they exhibit biological markers consistent with stroma at the site of wound repair. In prostate cancer, stroma is composed of fibroblasts, myofibroblasts, endothelial cells and immune cells. Predominant cells in the tumorous stroma are, however, fibroblasts/myofibroblasts. They are responsible for the synthesis, deposition and remodeling of the ECM. Epithelial tumorous cells, in interaction with stromal cells and with the help of various molecules of ECM, create a microenvironment suitable for cancer cell proliferation, movement, and differentiation. In this review, we discussed the role of different stromal components in prostate cancer as well as their potential prognostic and therapeutic significance.

The presence of extensive retraction clefts in invasive breast carcinomas correlates with lymphatic invasion and nodal metastasis and predicts poor outcome: a prospective validation study of 2742 consecutive cases

We previously reported that the presence of extensive retraction clefts (RC) in breast cancers correlates with increasing tumor size and grade as well as lymphatic tumor spread and predicts poor outcome. This study is a prospective validation of our prior results. Consecutive cases of invasive breast carcinoma (n=2742) were reviewed to determine the diagnoses, including histologic type, grade, presence of lymphovascular invasion (LVI), and extent of RC. No differences were found in the extent of RC between corresponding core needle biopsy and surgical samples. Extent of RC showed a significant correlation with tumor size, grade, LVI, and nodal metastasis in both core needle biopsy and surgical specimens. These associations remained significant in subset analyses of small (≤1 cm), node-negative and node-positive tumors. Extensive RC predicted poor recurrence-free (P<0.0001) and overall (P<0.0001) survival and remained significant in subset analyses of node-negative (P=0.0015 and 0.0021, respectively) and node-positive (P=0.0039 and 0.0214, respectively) cases. Carcinomas without LVI but extensive RC were associated with better outcome than carcinomas with LVI but worse than those without LVI and low RC. This prospective study confirms that the presence of extensive RC in invasive breast carcinomas correlates with aggressive tumor features and lymphatic tumor spread. Extensive RC appears to be an independent factor predictive of poor outcome in node-negative and node-positive disease. Our results support the hypothesis that RCs are the morphologic reflection of biological changes in tumor cells playing a role in lymphatic tumor spread and likely represent an early stage of LVI with similar clinical implications.

Mucin-producing tumors and tumor-like lesions involving the prostate: a comprehensive review

Mucin-producing tumors of the prostate include both primary and secondary tumors with mucinous differentiation or features involving the prostate gland. These tumors are relatively rare and have variable prognostic and therapeutic implications. Primary mucinous (colloid) adenocarcinoma of the prostate is defined as prostatic adenocarcinoma with mucinous differentiation involving 25% or more of the entire tumor. Another primary tumor of the prostate that may have mucinous features is primary mucin-producing urothelial-type adenocarcinoma of the prostate (mucinous prostatic urethral adenocarcinoma). Primary mucin-producing urothelial-type adenocarcinoma of the prostate is a distinct entity that typically arises from the prostatic urethra possibly from urethritis glandularis or glandular metaplasia with malignant transformation, and it is analogous to adenocarcinoma with mucinous differentiation arising from the urinary bladder. Signet ring cell tumors of the prostate, though rare, may also have mucinous features. Secondary tumors with mucinous differentiation that may involve the prostate include adenocarcinomas of the urinary bladder and colorectum. Pathologists should also be aware of mucin-producing tumor-like lesions involving the prostate, including mucinous metaplasia, and benign Cowper glands that may mimic malignancy. Herein we present an updated and comprehensive review of the clinicopathologic, immunohistochemical, molecular, and prognostic features of mucinous tumors and tumor-like lesions involving the prostate gland, with emphasis on mucinous prostatic adenocarcinoma and its mimickers, including potential diagnostic pitfalls.

Determination of optical coefficients and fractal dimensional parameters of cancerous and normal prostate tissues

Optical extinction and diffuse reflection spectra of cancerous and normal prostate tissues in the 750 to 860 nm spectral range were measured. Optical extinction measurements using thin ex vivo prostate tissue samples were used to determine the scattering coefficient (μ(s)), while diffuse reflection measurements using thick prostate tissue samples were used to extract the absorption coefficient (μ(a)) and the reduced scattering coefficient (μ'(s)). The anisotropy factor (g) was obtained using the extracted values of μ(s) and μ'(s). The values of fractal dimension (D(f)) of cancerous and normal prostate tissues were obtained by fitting to the wavelength dependence of μ'(s). The number of scattering particles contributing to μ(s) as a function of particle size and the cutoff diameter d(max) as a function of g were investigated using the fractal soft tissue model and Mie theory. Results show that d(max) of the normal tissue is larger than that of the cancerous tissue. The cutoff diameter d(max) is observed to agree with the nuclear size for the normal tissues and the nucleolar size for the cancerous tissues. Transmission spectral polarization imaging measurements were performed that could distinguish the cancerous prostate tissue samples from the normal tissue samples based on the differences between their absorption and scattering parameters.

Periacinar retraction clefting in nonneoplastic and neoplastic prostatic glands: artifact or molecular involvement

A space between neoplastic acini and prostatic stroma is not rare and studies have interpreted this as an artifact, considering the absence of endothelial cells indicating vascular invasion. Thus, the aims of this work were to characterize and correlate the occurrence and extent of retraction clefting with the reactivities of α and β dystroglycan (αDG, βDG), laminin, matrix metalloproteinase 2 (MMP-2), p63, insulin-like growth factor 1(IGF-1), vimentin, and fibroblast growth factor 2 (FGF-2). The study was based on nonneoplastic and neoplastic prostatic tissues obtained from necropsies and retropubic radical prostatectomies. The results showed that periacinar retraction clefting was significantly more frequent in prostatic carcinoma samples than in normal prostatic acini. Most of the neoplastic acini (72.0%) showed retraction clefting of more than 50% of circumference, which were significantly more frequent in Gleason score 7 and 6. Decreased collagen and reticular and elastic fibers were verified in the stroma around neoplastic acini. Weak and discontinuous αDG, βDG, and laminin immunoreactivities and intensified MMP-2, vimentin, IGF-1 and FGF-2 immunoreactivities were verified in the neoplastic acini; p63 immunoreactivity was negative in all carcinomas. Thus, these findings showed that the lack of epithelial basal cells, DGs, and laminin and increased MMP-2, IGF-1, and FGF-7 could be considered important pathways in periacinar retraction occurrence. This study demonstrated the origin of and the biological mechanisms responsible for periacinar retraction clefting in prostatic carcinoma.

Extensive retraction artefact predicts biochemical recurrence-free survival in prostatic carcinoma

AIMS

To determine whether the presence and extent of peritumoral retraction artefact could be used to predict biochemical recurrence-free survival in prostatic carcinoma.

METHODS AND RESULTS

The study included 162 consecutive patients treated by radical retropubic prostatectomy and bilateral lymphadenectomy for clinically localized prostatic carcinoma. A variable degree of retraction artefact was present in all 162 analysed tumours. The extent of retraction artefact in prostatic carcinomas ranged from 5% to 55% with a median value of 15% (interquartile range 10-25%). We found no correlation between the extent of retraction artefact in the tumours and patient's age (P=0.608), preoperative (P=0.362) and postoperative (P=0.279) Gleason score or lymph node metastases (P=0.084). In contrast, the extent of retraction artefact correlated with high preoperative prostate-specific antigen (P<0.001), short follow-up time (P<0.001), seminal vesicle invasion and/or extracapsular extension of the tumour (T3 stage tumours) (P<0.001) and positive surgical margins (P<0.001). Furthermore, extensive retraction artefact was associated with poor biochemical recurrence-free survival in both univariate (P<0.001) and multivariate analyses (P=0.013).

CONCLUSION

The presence of extensive retraction artefact in prostatic carcinoma correlates with tumour characteristics signifying aggressive behaviour and indicates poor biochemical recurrence-free survival.

Invasive ductal carcinomas of the breast showing partial reversed cell polarity are associated with lymphatic tumor spread and may represent part of a spectrum of invasive micropapillary carcinoma

Invasive micropapillary carcinomas (IMPC) of the breast are aggressive tumors frequently associated with lymphatic invasion and nodal metastasis even when micropapillary (MP) differentiation is very focal within the tumors. We have noticed that some breast carcinomas showing lymphatic spread but lacking histologic features of IMPC have occasional tumor cell clusters reminiscent of those of IMPC without the characteristic prominent retraction artifact. To study the clinicopathologic significance of such features, we prospectively selected 1323 invasive ductal carcinomas and determined the presence and extent of MP differentiation and retraction artifact in the tumors. One representative tumor block per case was used for immunostaining for epithelial membrane antigen (EMA). Partial reverse cell polarity (PRCP) was defined as prominent linear EMA reactivity on at least part of the periphery of tumor cell clusters usually associated with decreased cytoplasmic staining. The clinicopathologic features of carcinomas with PRCP were compared with IMPC and invasive ductal (no special type) carcinomas without this feature. Of the 1323 cases, 96 (7.3%) and 92 (7.0%) showed MP features and the presence of PRCP, respectively. We found that the presence of both PRCP and MP features were strongly associated with decreased cytoplasmic EMA immunoreactivity and the presence of lymphatic invasion and nodal metastasis, even if such features were present only very focally. Our results suggest that breast carcinomas with PRCP may have the same implication as MP differentiation and these tumors may represent part of a spectrum of IMPC. Complete or partial reversal of cell polarity may play a significant role in lymphatic tumor spread.

TMPRSS2-ERG gene fusion is associated with low Gleason scores and not with high-grade morphological features

TMPRSS2-ERG gene rearrangement is seen in about half of clinically localized prostate cancers, yet controversy exists with regard to its prognostic implications. Similarly, the relationship of TMPRSS2-ERG fusion to Gleason score and morphology remains uncertain. We assigned Gleason scores and recorded morphological features for 521 clinically localized prostate cancers sampled in triplicate and arrayed in eight tissue microarray blocks. Fluorescence in situ hybridization was performed to delineate TMPRSS2-ERG aberrations. Using maximum Gleason score, based on three core evaluation, and overall Gleason score, based on prostatectomy sections, Fisher's exact test was performed for tumors with TMPRSS2-ERG translocation/deletion, copy number increase (≥ 3) of the TMPRSS2-ERG region without translocation/deletion, and copy number increase and concomitant translocation/deletion. In all, 217 (42%) translocation/deletion and 30 (5.9%) copy number increase-alone cases were detected. Among 217 translocation/deletion cases, 32 had translocation/deletion with copy number increase. In all, 237, 200, and 75 cancers had maximum core-specific Gleason score of 6, 7, and 8-10, respectively. Tumors with translocation/deletion tended toward lower Gleason scores than those without (P=0.002) with similar results for overall Gleason score (P=0.02); copy number increase cases tended toward higher Gleason scores than those without (P<0.001). Gleason score of 8-10 tumors demonstrated lower odds of translocation/deletion (odds ratio (OR) 0.38; 95% CI 0.21-0.68) and higher odds of copy number increase alone (OR 7.33; 95% CI 2.65-20.31) or copy number increase+translocation/deletion (OR 3.03; 95% CI 1.12-8.15) relative to Gleason score of <7 tumors. No significant difference in TMPRSS2-ERG incidence was observed between patients with and without cribriform glands, glomerulations, signet-ring cells, or intraductal cancer (P=0.821, 0.095, 0.132, 0.375). TMPRSS2-ERG gene fusion is associated with lower core-specific and overall Gleason scores and not with high-grade morphologies. Conversely, TMPRSS2-ERG copy number increase, with or without rearrangement, is associated with higher Gleason score. These findings indicate that translocation/deletion of TMPRSS2-ERG is not associated with histological features of aggressive prostate cancer.

The presence of micropapillary features and retraction artifact in core needle biopsy material predicts lymph node metastasis in breast carcinoma

Retraction artifact around tumor cell nests is a characteristic feature of invasive micropapillary carcinoma (IMPC), a special type of breast cancer commonly associated with nodal metastasis. We have recently reported that the extent of retraction artifact in usual invasive ductal carcinomas (IDC) is also a strong predictor of nodal metastasis. We examined whether the presence and extent of micropapillary features and retraction artifact in core needle biopsy of breast cancers can predict nodal metastasis in a prospective series of 47 IMPC and 424 IDC. Micropapillary features were present on core needle biopsy in 28 of 47 IMPC cases. Nodal metastases were found in 21 of 28 and 14 of 19 IMPC cases with and without micropapillary features present on core needle biopsy, respectively. Lymph node metastasis was significantly associated with the presence of micropapillary features, but not with its extent within these tumors. The presence of extensive retraction artifact in core needle biopsy samples of IDC also showed a significant association with nodal metastasis. Our results indicate that the presence of micropapillary features or extensive retraction artifact on core needle biopsy of breast carcinoma can predict nodal metastasis. Our results support the notion that the characteristic clear spaces separating the tumor cells from the stroma in IMPC and IDC of the breast are not a random artifactual phenomenon simply resulting from tissue fixation and processing, but rather they are likely related to altered tumor-stromal interactions, which might have an important role in lymphatic tumor spread.

Periacinar retraction clefting in proliferative prostatic atrophy and prostatic adenocarcinoma

AIMS

To evaluate the presence and extent of periacinar retraction clefting in proliferative prostatic atrophy and carcinoma in radical prostatectomy specimens.

METHODS

Atrophic foci and neoplastic glands were analysed in specimens from 50 patients who underwent radical prostatectomy. Analysed atrophic glands were classified in two main groups, proliferative atrophy (PA) and proliferative inflammatory atrophy (PIA); each group was subclassified into simple atrophy (SA) and postatrophic hyperplasia (PAH). According to the presence and extent of periacinar retraction clefting, atrophic and neoplastic glands were classified as: group 1, glands without clefts or with clefts affecting 50% of the circumference in <50% of examined glands; and group 3, glands with clefts that affected >50% of the circumference in >or=50% of examined glands.

RESULTS

Forty-four (88.0%) atrophic foci were without periacinar clefts or clefts were present in less than half of the gland circumference (group 1). In 6 (12.0%), atrophic foci clefts affected >50% of gland circumference (groups 2 and 3). Forty-five (90.0%) carcinomas were with clefts which affected more than 50% of gland circumference (groups 2 and 3); and in five carcinomas only, clefts were not found or affected <50% of gland circumference (group 1).

CONCLUSION

Results indicate that periacinar retraction clefting represents a reliable criterion in differential diagnosis between proliferative atrophy and carcinoma.

Intraluminal crystalloids are highly associated with prostatic adenocarcinoma on concurrent biopsy specimens

Prostatic crystalloids are intraluminal eosinophilic structures with variable size and shape. Their presence has been described in conjunction with the occurrence of prostatic adenocarcinoma (pCA). We herein report the association of crystalloids and pCA in a prospective trial utilizing an extended multi-site transrectal ultrasound-guided (TRUS) prostate biopsy protocol. Three hundred and forty-four consecutive patients were prospectively enrolled at the Dallas Veterans Administration Hospital from November 2002 to September 2003. Indications for biopsy included a prostate-specific antigen (PSA) > or =4 ng/ml and/or abnormal digital rectal exam. A single pathologist evaluated all biopsy cores and documented the presence or absence of significant histopathologic features. Univariate and multivariate logistic regression analysis were applied to test the association of these features with the presence of pCA on concurrent biopsy. Median number of core biopsies per patient was 12 (range 3-36). Overall cancer detection rate was 42.7%. pCA was diagnosed in 66 (81.5%) of 81 patients with crystalloids, 70 (69.3%) of 101 patients with high-grade prostatic intraepithelial neoplasia (HGPIN), and 32 (84.2%) of 38 patients with both HGPIN and crystalloids on biopsy. Multivariate analysis identified crystalloids (RR 4.53, 95% CI 2.30-8.88) and HGPIN (RR 3.20, 95% CI 1.84-5.57) as independent predictors of the presence of cancer on concurrent biopsy (P<0.001). In this prospective analysis, crystalloids were significantly associated with pCA on concurrent biopsy and more predictive of the presence of pCA than HGPIN. These findings suggest that the presence of crystalloids alone or in combination with HGPIN in prostate biopsies may be a more compelling indication for repeat biopsy than HGPIN alone.

Extensive retraction artifact correlates with lymphatic invasion and nodal metastasis and predicts poor outcome in early stage breast carcinoma

Retraction artifact resulting in clear spaces around tumor cell nests is frequently seen in histologic material and may present difficulty in their differentiation from lymphovascular invasion. We noticed that retraction artifact seemed to be more common around groups of breast cancer cells compared with benign acini, and when extensively present, metastasis to axillary lymph nodes was often seen. Thus, we performed a study of 304 cases of stage pT1 and pT2 breast carcinomas to test our hypothesis that extensive retraction artifact in tumors correlates with lymphatic spread and outcome. Tumors were evaluated to determine the presence and extent of retraction artifact around tumor cell nests and the presence of lymphatic invasion. Lymphatic invasion was confirmed by D2-40 immunostaining. The extent of retraction artifact in tumors was correlated with clinicopathologic tumor features and patient outcome. Variable degree of retraction artifact was present in 183 of 304 (60%) invasive carcinomas, with its extent ranging from 0% to 90% (median 5%). The extent of retraction artifact showed a significant correlation with tumor size, histologic type, histologic grade, presence of lymphovascular invasion, and nodal metastasis. Further, extensive retraction artifact was significantly associated with poor overall and disease-free survival in both univariate and multivariate analyses. We propose that the apparent retraction of the stroma from cells of invasive breast carcinoma on routine histologic sections is not a phenomenon merely due to inadequate fixation as currently believed. Rather, it likely signifies important biologic changes that alter tumor-stromal interactions and contribute to lymphatic spread and tumor progression.

Periacinar Clefting and p63 Immunostaining in Prostatic Intraepithelial Neoplasia and Prostatic Carcinoma

The aim of the present study was to correlate the presence and extent of retraction clefting and the expression of p63 in neoplastic glands and glands with prostatic intraepithelial neoplasia (PIN) in needle core biopsies. We analyzed needle core biopsies from 28 patients with PIN and 41 patients with adenocarcinoma. Neoplastic glands and those with PIN were analyzed on high power field (400x) and classified in three groups according to the extent of clefting. Immunohistochemical staining was performed following Microwave Streptavidin ImmunoPeroxidase (MSIP) protocol on DAKO TechMate Horizon automated immunostainer. Periacinar retraction clefting was significantly more prominent in prostatic carcinoma compared to PIN (p<0.0001) and nonneoplastic glands (p<0.0001). There was no difference between normal glands and PIN regarding clefting (p=0.8064). p63 was positive around the whole circumference in 12 out of 28 cases with PIN, and discontinuously positive in remaining 16 PIN cases suggesting initial disruption of the basal cell layer. p63 immunostaining was also positive in all nonneoplastic glands, and negative in all carcinomas. We conclude that retraction clefting was associated with cancer and lack of basal cells, but not with PIN. The relationship between clefting and p63 immunostaining in prostatic cancer should be further analyzed.

Charcot-Leyden crystals in a prostatic adenocarcinoma

A transrectal needle biopsy from a 63-year-old man was decided because of a high prostatic spesific antigen in the blood, and a hard right lobe in rectal examination. 10 examples were taken from each lobe. In 1 of 4 of the examples from the left lobe, which contained a small focus of adenocarcinoma, numerous eosinophils were observed to surround the carcinomatous focus and attack the carcinoma cells. Uniquely, at the same focus Charcot-Leyden crystals could be seen in the intraluminal space and stromal area. A carcinoma oriented eosinophil accumulation, and Charcot-Leyden crystals in prostate was not described before.

Current prostate biopsy interpretation: criteria for cancer, atypical small acinar proliferation, high-grade prostatic intraepithelial neoplasia, and use of immunostains

CONTEXT

The past decade has brought major changes in prostate biopsy sampling, interpretation, and reporting.

OBJECTIVE

To summarize current information on diagnostic decision making, Gleason grading, "atypical" diagnoses, and use of immunostaining.

DATA SOURCES

Pertinent literature from 1985 to 2005 is reviewed, emphasizing recent findings.

CONCLUSIONS

Diagnosis begins by evaluating a focus of atypical single-cell layer lined acini according to the 3 minimal diagnostic criteria for cancer: an infiltrative pattern, nuclear enlargement and hyperchromasia, and prominent nucleoli. The Gleason score and linear extent or percent of each core containing cancer should be reported. Atypical small acinar proliferation suspicious for malignancy designates foci that have either qualitative or quantitative limitations in atypia precluding a definite cancer diagnosis. It has about a 3% incidence as an isolated finding. Contemporary studies indicate a 39% predictive value for cancer on repeat biopsy. Isolated high-grade prostatic intraepithelial neoplasia has a 3% to 14% incidence and predicts cancer on repeat biopsy in 23% of cases. Immunostaining for a marker of benign prostate (cytoplasmic keratin 34betaE12 or nuclear p63) and a marker of cancer (alpha-methylacyl coA racemase, clone P504S) may or may not resolve atypical small acinar proliferation diagnoses. Performance of 34betaE12 and P504S immunostains resolved 76% of atypical small acinar proliferation diagnoses per consensus of 3 urologic pathologists studied; a technical limitation is preservation of the focus in question on the levels used for immunostaining.

Current practice of diagnosis and reporting of prostate cancer on needle biopsy among genitourinary pathologists

As there is a lack of hard data in the literature about many of the issues relating to diagnosing and reporting prostate cancer, we sought to survey current practices. A questionnaire was sent to 93 genitourinary pathologists with a response rate of 69%. Almost all respondents (95%) used formalin as fixative for needle biopsies. Unstained intervening sections were retained by 47%. Three levels of needle biopsies were used routinely by 63%. For verification of a diagnosis of cancer, high-molecular-weight cytokeratin was still the most commonly used immunohistochemical marker (91%), followed by p63 (58%) and alpha-methylacyl-CoA-racemase (50%). Features considered pathognomonic for cancer were glomeruloid bodies (58%), collagenous micronodules (64%), circumferential perineural invasion (84%), and growth in fat (36%). With none of these present, 39% required a minimum of 2 to 10 glands (median, 3) to diagnose cancer, whereas the others had no lower limit. A Gleason score was always given to even minute cancer foci by 86% and typically a Gleason score 6 was assigned (77%). Perineural invasion was mentioned by 86%. The extent of cancer on needle biopsies was quantified by all respondents with number of involved cores (80%) being the most commonly used measure. Linear extent was estimated by almost all, either as a percentage (80%) or millimeters of cancer length (41%) or both (22%). Measuring cancer from end to end or subtracting intervening benign tissue were almost equally common. For those general pathologists who would like to be in the mainstream of most urological pathologists, our survey data provide a guideline on how to diagnose and report prostate cancer.

Number and location of nucleoli and presence of apoptotic bodies in diagnostically challenging cases of prostate adenocarcinoma on needle biopsy

There is limited published data regarding the significance of the number or position of nucleoli and the presence of apoptotic bodies in diagnostically challenging cases of adenocarcinoma of the prostate on needle biopsy material. One hundred consecutive prostate cancers on needle biopsy were sent because of diagnostic difficulty to an expert in urological pathology, and the remaining normal benign prostatic glands on the same core were evaluated for the number and location of nucleoli and for the presence of mitotic figures and apoptotic bodies. The Gleason scores of the cases were 6 (86%), 7 (9%), and 8 to 10 (5%). For comparison, the same parameters were evaluated in mimickers of cancer on needle biopsy from other cases, including partial atrophy (n = 135), fully developed atrophy (n = 89), adenosis (n = 50), prostate glands with acute inflammation (n = 50), and high-grade prostatic intraepithelial neoplasia (n = 100). Findings were recorded under high dry magnification (x40) using hematoxylin and eosin-stained sections. Although the number and position of nucleoli did not discriminate between cancer and benign mimickers, mitotic figures and apoptotic bodies were more commonly seen in cancer. Apoptotic bodies in particular were seen fairly frequently (34%) in prostatic adenocarcinoma (also seen in 13% of high-grade prostatic intraepithelial neoplasia), yet rarely in benign mimickers on needle biopsy. Our findings indicate that the presence of apoptotic bodies should be added to the list of histological features that are helpful in the diagnosis of challenging cases of prostate cancer on needle biopsy.

Diagnostic utility of immunohistochemistry in morphologically difficult prostate cancer: review of current literature

Varma M & Jasani B (2005) Histopathology47, 1-16 Diagnostic utility of immunohistochemistry in morphologically difficult prostate cancer: review of current literatureImmunohistochemistry is widely used to distinguish prostate cancer from benign mimics and to establish the prostatic origin of poorly differentiated carcinoma. We critically review the recent advances in prostate cancer immunohistochemistry, including the introduction of newer basal cell markers such as p63 and the discovery of the overexpression of alpha-methylacyl coenzyme A racemase (AMACR) in prostate cancer. The description of newer urothelial markers to aid the distinction of prostate cancer from urothelial carcinoma is also presented together with refinements in the quality control of PSA and PSAP immunostaining. Although AMACR is a useful immunohistochemical marker for prostate cancer, it has significant limitations. These limitations are discussed and the need for interpreting AMACR immunoreactivity in the appropriate morphological context and in conjunction with basal call markers is emphasized. We also describe the utility of an immunohistochemical panel composed of PSA, PSAP and high molecular weight cytokeratin for distinguishing poorly differentiated prostate cancer from high-grade urothelial carcinoma. A morphological differential diagnosis based selection of immunohistochemical markers is highlighted as a novel approach in the diagnosis of prostate cancer in routine surgical pathology practice.

Minute Foci of Gleason Score 8-10 on Prostatic Needle Biopsy

Prostatic needle biopsies showing high-grade cancer typically contain abundant tumor. However, the histologic features of a minute focus of high-grade cancer on biopsy have not been well studied. A total of 100 cases with a single minute focus (< or = 1 mm) of Gleason score (GS) 8-10 adenocarcinoma were identified from a large consultative service, systematically studied, and compared with the submitting institutions' provisional diagnoses. The mean size of the minute foci was 0.52 mm. A total of 29 cases were GS 8 with cribriform glands (n = 15), poorly formed glands (n = 6), fused glands (n = 3), or combinations of the three (n = 5). A total of 38 cases were GS 9, with: single cells and poorly formed glands (n = 20); extremely poorly formed glands/borderline pattern 4/5 (n = 4); combinations of single cells, sheets, or nests of cells mixed with glands that were either poorly formed, cribriform, or fused (n = 14). A total of 33 cases were GS 10, with single cells (n = 23), single cells with nests (n = 9), or single cells with sheets of cells (n = 1). A total of 69 foci were located adjacent to benign glands, while 31 were on the edge or at the end of the core. Perineural invasion was observed in only 1 case. A total of 72 cases showed moderate to abundant amphophilic cytoplasm. Frequent prominent nucleoli (n = 11), mitoses (n = 8), and apoptotic bodies (n = 11) were infrequently observed. Of 59 cases with known provisional diagnoses, 46 were diagnosed as atypical (n = 37) or as cancer with GS < 8 (n = 9). Pathologists must be attuned to the complex and varied architectural patterns seen in low-volume, high-grade prostate cancer as its diagnosis has both important prognostic and therapeutic implications.

Proliferative lesions of prostate: a multivariate approach to differential diagnosis

Prostatic needle biopsies from 142 patients were studied: 61 cases were "benign", 19 atypical small acinar proliferation, 31 high-grade prostatic intraepithelial neoplasia, and 31 adenocarcinoma. Using univariate analysis of 46 previously described morphological features, 16 variables were selected, which were followed by multivariate discriminant analysis. Of these parameters, seven (glandular fusion, crystalloids, nucleolomegaly, papillary architecture, visibility of basal cell layer, areas of normal luminal cell nucleus/cytoplasm ratio and areas of high luminal cell nucleus/cytoplasm ratio) remained significant in discriminating the groups. Multivariate analysis selected a small panel of histological features as those most helpful in the differential diagnosis of proliferative lesions in prostate biopsies.

Corpora amylacea in adenocarcinoma of the prostate: incidence and histology within needle core biopsies

Corpora amylacea in the prostate are a frequent finding in benign acini, but are only rarely observed in adenocarcinoma. To determine the incidence and comparative histopathology of this finding, we prospectively reviewed all consecutive needle core biopsies (excluding consultations) received at Bostwick Laboratories between December 2001 and July 2003. Among 5130 cases of adenocarcinoma (34% of 15,279 total needle biopsy cases), we identified 19 (31 biopsy specimens) with corpora amylacea within cancerous acini (0.4% incidence). Patients ranged in age from 51 to 89 years (mean, 68 years). The corpora amylacea were located within cancers with Gleason pattern 3 (28 of 31 specimens), Gleason pattern 4 (one specimen), and Gleason pattern 5 (two specimens), and ranged from less than 0.1-0.3 mm in diameter. Coexistent eosinophilic proteinaceous debris was noted in all 31 specimens, luminal mucin in 19, crystalloids in 15, and collagenous micronodules in two specimens. Our results indicate that the incidence of corpora amylacea in adenocarcinoma is low, but the presence of such inclusions cannot be used to exclude malignancy.

The use of morphological characteristics and texture analysis in the identification of tissue composition in prostatic neoplasia

Quantitative examination of prostate histology offers clues in the diagnostic classification of lesions and in the prediction of response to treatment and prognosis. To facilitate the collection of quantitative data, the development of machine vision systems is necessary. This study explored the use of imaging for identifying tissue abnormalities in prostate histology. Medium-power histological scenes were recorded from whole-mount radical prostatectomy sections at x 40 objective magnification and assessed by a pathologist as exhibiting stroma, normal tissue (nonneoplastic epithelial component), or prostatic carcinoma (PCa). A machine vision system was developed that divided the scenes into subregions of 100 x 100 pixels and subjected each to image-processing techniques. Analysis of morphological characteristics allowed the identification of normal tissue. Analysis of image texture demonstrated that Haralick feature 4 was the most suitable for discriminating stroma from PCa. Using these morphological and texture measurements, it was possible to define a classification scheme for each subregion. The machine vision system is designed to integrate these classification rules and generate digital maps of tissue composition from the classification of subregions; 79.3% of subregions were correctly classified. Established classification rates have demonstrated the validity of the methodology on small scenes; a logical extension was to apply the methodology to whole slide images via scanning technology. The machine vision system is capable of classifying these images. The machine vision system developed in this project facilitates the exploration of morphological and texture characteristics in quantifying tissue composition. It also illustrates the potential of quantitative methods to provide highly discriminatory information in the automated identification of prostatic lesions using computer vision.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Periacinar retraction clefting in the prostatic needle core biopsies: an important diagnostic criterion or a simple artifact?

The diagnosis of prostatic adenocarcinoma in needle core biopsy is based on major and supportive criteria. One of the supportive criteria is the presence of retraction clefting around neoplastic glands. We analyzed a series of 137 prostatic cancer cases diagnosed by needle core biopsy to determine the frequency, extent and criteria for periacinar retraction clefting. Clefting was analyzed on ten neoplastic and ten normal glands in three different high power fields. One-third or more glands with clefts affecting more than 50% of circumference were significantly more common in tumors (51.8%) than in benign glands (8%) (P<0.0001). A stricter criterion that designated as positive the cases with at least 50% of neoplastic glands (15 of 30) with clefts that affected more than 50% of circumference revealed clefts in only 15.3% of the malignant cases but none in benign cases (0%) (P<0.0001). Regardless of their extension, 15 or more glands with clefts were also more prominent in malignant cases (86.9%) than in benign cases (20.4%) (P<0.0001). We conclude that periacinar retraction clefting represents a reliable criterion for diagnosis of the prostatic adenocarcinoma, especially in cases with clefts affecting more than 50% of circumference in at least 50% of suspicious glands.

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.

Pathogenesis and significance of collagenous micronodules of the prostate

Collagenous micronodules, also known as mucinous fibroplasia, are microscopic structures characterized by the presence of small eosinophilic nodules in areas immediately adjacent to prostatic glandular epithelium. The pathogenesis of collagenous micronodules is unknown, although their relation with mucin has been suggested. The objective of our study was to analyze the structural characteristics of collagenous micronodules by using histochemistry, immunohistochemistry, and electron microscopy to elucidate the pathogenesis of this lesion. We analyzed 15 cases of prostate adenocarcinoma (12 prostatectomy specimens and 3 biopsy specimens) with collagenous micronodules. The collagenous micronodules were closely associated with well-formed malignant glands, where tumor cells exhibited basophilic to amphophilic cytoplasm. Occasionally, intraluminal collagen fragments were observed within malignant but not benign glands. Collagenous micronodules were not associated with mucin, confirmed by negative stainings of mucicarmin or alcian blue in all the collagenous micronodules analyzed in this study. Therefore, the term "mucinous fibroplasia" may not be accurate. Collagenous micronodules stained weakly positive for periodic acid-Schiff. Trichrome stain highlighted the presence of collagenous micronodules as distinct blue structures. Collagen IV and laminin immunostaining performed in 12 cases outlined the micronodules with minimal staining in the center. These findings indicated that collagenous micronodules consisted of predominantly collagen fragments admixed with basement membrane material. Ultrastructurally, they were composed of fragmented banded collagen fibrils surrounded by the basement membrane material. Collagenous micronodules are formed by subepithelial accumulations of fragmented collagen fibers, possibly related to the digestion by collagenase produced by prostatic adenocarcinoma cells.