High molecular weight cytokeratin antibody (clone 34betaE12): a sensitive marker for differentiation of high-grade invasive urothelial carcinoma from prostate cancer

The secondary tumor of the prostate derived from upper tract urothelial carcinoma: An autopsy case

INTRODUCTION

Metastatic urothelial carcinomas are common in lung, liver, and lymph nodes. We present rare secondary tumor of the prostate metastasized from upper tract urothelial carcinoma.

CASE PRESENTATION

An 87-year-old man was diagnosed as urothelial carcinoma of left upper tract and bladder. Only transurethral resection of bladder tumor was performed as palliative therapy to control hematuria. Thereafter, the tumor of left upper tract showed aggressive progression with multiple metastases involving lymph nodes and bilateral lungs. Finally, autopsy revealed swelling of left kidney due to tumor growth and systemic cancer disseminations involving bilateral lungs and renal hilar lymph nodes. In addition, prostate tumor was found incidentally. Histological examination including immunohistochemistry revealed the prostate tumor as metastatic tumor from urothelial carcinoma of left renal pelvis.

CONCLUSION

We reported rare secondary tumor of the prostate, derived from upper tract urothelial carcinoma. Further consideration would be required to provide better knowledge of the disease.

Aberrant GATA3 Staining in Prostatic Adenocarcinoma: A Potential Diagnostic Pitfall

Distinguishing between poorly differentiated urothelial carcinoma and high-grade prostatic adenocarcinoma is a common challenge in genitourinary pathology, particularly when the tumor involves the bladder neck or prostatic urethra. Clinically, the distinction between these 2 tumors can also be difficult. Proper diagnosis in these patients is essential as they have differing prognoses and clinical management. GATA3 is thought to be a sensitive and relatively specific marker of urothelial carcinoma. However, there is scant data regarding GATA3 labeling of high-grade prostatic adenocarcinoma. The aim of this study is to describe rare cases with strong aberrant GATA3 staining in prostatic adenocarcinoma as a potential diagnostic pitfall. We identified 9 cases of prostatic adenocarcinoma with aberrant positive GATA3 staining from 2015 to 2020 as part of a large consultation service at our institution. All 9 cases were grade group 5, 8 had a Gleason score of 5+5=10 and 1 had a score of 4+5=9. Five of the cases were from the prostate, 3 from the urinary bladder, and 1 from the prostatic urethra. All cases were morphologically typical of high-grade prostatic adenocarcinoma, although were sent for consultation due to uncertainty in the diagnosis. GATA3 positivity was strong, diffuse in 4 cases; strong, patchy in 2 cases and strong, focal in 3 cases. All cases were positive for NKX3.1, 6 positive for p501s, and 6 positive for PSA, with 7/9 cases showing expression of at least 2 prostate-specific markers. The current study describes that rare cases of prostatic adenocarcinoma can show focal or diffuse strong staining for GATA3. In order to avoid this diagnostic pitfall, undifferentiated carcinomas involving the prostate, bladder neck, or trigone should be evaluated not only with GATA3 but also prostate-specific markers.

An Algorithmic Immunohistochemical Approach to Define Tumor Type and Assign Site of Origin

Immunohistochemistry represents an indispensable complement to an epidemiology and morphology-driven approach to tumor diagnosis and site of origin assignment. This review reflects the state of my current practice, based on 15-years' experience in Pathology and a deep-dive into the literature, always striving to be better equipped to answer the age old questions, "What is it, and where is it from?" The tables and figures in this manuscript are the ones I "pull up on the computer" when I am teaching at the microscope and turn to myself when I am (frequently) stuck. This field is so exciting because I firmly believe that, through the application of next-generation immunohistochemistry, we can provide better answers than ever before. Specific topics covered in this review include (1) broad tumor classification and associated screening markers; (2) the role of cancer epidemiology in determining pretest probability; (3) broad-spectrum epithelial markers; (4) noncanonical expression of broad tumor class screening markers; (5) a morphologic pattern-based approach to poorly to undifferentiated malignant neoplasms; (6) a morphologic and immunohistochemical approach to define 4 main carcinoma types; (7) CK7/CK20 coordinate expression; (8) added value of semiquantitative immunohistochemical stain assessment; algorithmic immunohistochemical approaches to (9) "garden variety" adenocarcinomas presenting in the liver, (10) large polygonal cell adenocarcinomas, (11) the distinction of primary surface ovarian epithelial tumors with mucinous features from metastasis, (12) tumors presenting at alternative anatomic sites, (13) squamous cell carcinoma versus urothelial carcinoma, and neuroendocrine neoplasms, including (14) the distinction of pheochromocytoma/paraganglioma from well-differentiated neuroendocrine tumor, site of origin assignment in (15) well-differentiated neuroendocrine tumor and (16) poorly differentiated neuroendocrine carcinoma, and (17) the distinction of well-differentiated neuroendocrine tumor G3 from poorly differentiated neuroendocrine carcinoma; it concludes with (18) a discussion of diagnostic considerations in the broad-spectrum keratin/CD45/S-100-"triple-negative" neoplasm.

Co-existence of mucin-producing urothelial-type adenocarcinoma of the prostate and inverted papilloma of the bladder

Adenocarcinoma of prostate with mucinous differentiation arising in the male urethra is extremely rare, with only 21 cases reported in the previous literature. A diagnosis of mucin-producing urothelial carcinoma of the prostate is based on the pathology, immunohistochemistry, and clinical examination by excluding the secondary adenocarcinoma of the prostate. We present a case of unexpected mucinous urothelial carcinoma of prostate with co-existing inverted papilloma of bladder in a 57-year-old man. The patient underwent transurethral resection of the prostate (TURP) and transurethral resection of a bladder tumour (TUR-Bt), and the pathologic result showed mucinous prostate carcinoma and bladder inverted papilloma. Immunohistological stain was negative for prostate-specific antigen (PSA), prostate-specific acid phosphatase (PSAP), and P63, but positive for cytokeratin 7 (CK 7), CK 20, clone 34βE12 and P504S. A complete endoscopic examination was performed to exclude the secondary adenocarcinoma of prostate. This case illustrates the clinical and pathological features of a rare and unexpected mucin-producing urothelial carcinoma of prostate in a bladder neoplasm patient.

S100P as a Marker for Urothelial Histogenesis: A Critical Review and Comparison With Novel and Traditional Urothelial Immunohistochemical Markers

S100P, or placental S100, is a member of a large family of S100 proteins and considered to be a promising immunohistochemical marker to support urothelial differentiation. This review synthesizes published data regarding the expression of S100P in urothelial carcinoma across histological grade and variant patterns, and in other malignancies, in an effort to summarize the state of understanding of this marker and evaluate its potential. We provide also a broad comparison of S100P with other contemporary and traditional urothelial markers and outline the potential utility of S100P in various diagnostically challenging scenarios. Taken in context, we recommend that to provide immunohistochemical support for consideration of urothelial differentiation, S100P may be included in a panel of markers (due to its high sensitivity), with better established (GATA3) and more specific (uroplakin 2) markers, for comparison with corresponding markers of other primary sites under consideration, depending on the clinical context. We emphasize that the overall most appropriate panel for any given case depends on the differential diagnosis engendered by the morphology encountered, and the constellation of clinical findings. As always with immunohistochemical panels, expected positive and negative markers for each diagnostic consideration should be included. Finally, since as of date there are no optimally sensitive or specific markers of urothelial differentiation, all final diagnoses relying on immunohistochemical support should be made in the appropriate clinical and histological context.

Morphologic Updates in Prostate Pathology

In the past several years, modifications have been made to the original Gleason system with resultant therapeutic and prognostic implications. Several morphologic variants of prostatic adenocarcinoma have also been described. Prostate pathology has also evolved over the years with the discovery and utility of new immunohistochemical stains. The topics discussed in this update include the Gleason grading system, prognostic grade grouping, variants of prostatic adenocarcinoma, and the application of immunohistochemistry to prostate pathology.

Immunohistochemical evaluation of novel and traditional markers associated with urothelial differentiation in a spectrum of variants of urothelial carcinoma of the urinary bladder

Data on immunohistochemical expression of novel and traditional urothelial markers in the wide range of urothelial carcinoma variants have so far been very limited. In this study, whole tissue sections from 130 bladder urothelial carcinoma and variants were stained with a panel of novel and traditional immunomarkers supportive of urothelial lineage. The positivity rates were as follows: (a) urothelial carcinomas with or without divergent differentiation: GATA3 (50%), S-100P (86%), uroplakin III (20%), thrombomodulin (40%), cytokeratin 7 (CK7) (80%), CK20 (55%), p63 (87%), and high molecular weight cytokeratin (HMCK) (89%); (b) urothelial carcinoma variants (micropapillary, plasmacytoid, nested, clear cell, and microcystic): GATA3 (88%), S-100P (96%), uroplakin III (33%), thrombomodulin (49%), CK7 (95%), CK20 (61%), p63 (69%), and HMCK (96%); and (c) undifferentiated carcinomas (lymphoepithelioma-like carcinoma, small cell carcinoma, sarcomatoid carcinoma and carcinoma with rhabdoid and giant cells): GATA3 (28%), S-100P (31%), uroplakin III (0%), thrombomodulin (22%), CK7 (50%), CK20 (3%), p63 (50%), and HMCK (49%). In urothelial carcinoma with squamous differentiation, GATA3 expression was lower (20%) in contrast to p63 and S-100P. In urothelial carcinoma with glandular differentiation, GATA3 (50%) and p63 (60%) expression was lower than S-100P (100%). p63 expression was relatively lower in micropapillary (54%) and plasmacytoid (50%) variants compared with the other urothelial carcinoma variants. This study provides comprehensive data for novel and traditionally used markers to support urothelial lineage in urothelial carcinoma variants. Our findings show that GATA3, S-100P, CK7, CK20, HMCK, and p63, in the appropriate differential diagnostic setting, are useful to support urothelial lineage of variant morphologies.

Molecular markers for prostate cancer in formalin-fixed paraffin-embedded tissues

Prostate cancer (PCa) is the most frequently diagnosed type of cancer in developed countries. The decisive method of diagnosis is based on the results of biopsies, morphologically evaluated to determine the presence or absence of cancer. Although this approach leads to a confident diagnosis in most cases, it can be improved by using the molecular markers present in the tissue. Both miRNAs and proteins are considered excellent candidates for biomarkers in formalin-fixed paraffin-embedded (FFPE) tissues, due to their stability over long periods of time. In the last few years, a concerted effort has been made to develop the necessary tools for their reliable measurement in these types of samples. Furthermore, the use of these kinds of markers may also help in establishing tumor grade and aggressiveness, as well as predicting the possible outcomes in each particular case for the different treatments available. This would aid clinicians in the decision-making process. In this review, we attempt to summarize and discuss the potential use of microRNA and protein profiles in FFPE tissue samples as markers to better predict PCa diagnosis, progression, and response to therapy.

A novel subtype of primary prostatic adenocarcinoma: A case report

The present study reports the novel case of an 81-year-old male with prostatic adenocarcinoma (PAC), whose histopathological study revealed a pure urothelial carcinoma (UC) that originated, however, from the prostatic glandular epithelium. The levels of serum prostate-specific antigen (PSA) were extraordinarily high in this patient. An MRI scan indicated a prostatic neoplasm and no malignant changes were observed in the bladder or other areas of the urinary tract. Hematoxylin and eosin-stained sections revealed a diagnosis of pure UC with no other form of differentiation (typical adenocarcinoma or squamous differentiation). The immunohistochemical findings were positive for PSA and P504S, and negative for CK7, CK20, 34βE12 and p63. A diagnosis of primary PAC (solid carcinoma) originating from the prostate was made based on the clinical, histopathological and immunohistochemical observations. This case was susceptible to diagnostic errors, however, a novel subtype of primary PAC was identified and termed the UC-like subtype.

A retrospective study of prostate cancer cases mimicking urothelial cell carcinoma of the bladder

BACKGROUND

Prostate cancer (PCa) originating from the prostate base may intrude into the urinary bladder and may be misdiagnosed as bladder cancer. In this retrospective study, we reviewed the clinic data on PCa cases which were initially misdiagnosed as bladder cancer in order to identify diagnostic methods that would allow a better differential diagnosis for PCa.

METHODS

Out of a total of 455 patients treated for PCa at our hospital between April 2003 and June 2011, 14 patients (3.1%) had been initially misdiagnosed as urinary bladder urothelial cell carcinoma. The clinical data on these 14 cases was retrieved and analyzed.

RESULTS

Of the 14 patients, 11 patients were eventually diagnosed with PCa after MRI examination, and seven out of these had PCa with bladder neck invasion. Prostate needle biopsy or transurethral resection of prostate (TURP) revealed that all 14 patients had adenocarcinoma of prostate with Gleason scores ranging from 7 to 9. Nine patients received TURP for hematuria or lower urinary tract blockage. The mean follow-up was 37 months, during which six patients survived.

CONCLUSIONS

As clinical presentation and in emergency settings, prostate cancer originating from the prostate base can be confused with bladder cancer originating from the neck or the triangle region of the urinary bladder. Serum prostate specific antigen (PSA) levels and digital rectal examination, in combination with transrectal ultrasound (TRUS), MRI, and prostate needle biopsy are valuable tools for definitive differential diagnosis of the basal prostate cancer.

Diagnostic utility of androgen receptor expression in discriminating poorly differentiated urothelial and prostate carcinoma

AIMS

Pathological separation of poorly differentiated urothelial and prostate carcinoma is difficult, but imperative because of the impact on patient management. Tumour morphology, in conjunction with a panel of immunohistochemistry (IHC), such as prostate-specific antigen (PSA), prostatic acid phosphatase (PSAP), CK7, CK20, p63 and high molecular weight keratins (HMWKs) are usually employed to resolve this issue. Androgen receptor (AR) expression is maintained in high-grade, undifferentiated prostate carcinoma, and thus, could be considered as a potentially useful adjunct to the conventional panel of markers.

METHODS

We performed an institutional review of all cases from 2006 to 2012 in which AR IHC had been performed to determine its diagnostic utility in discriminating between poorly differentiated urothelial and prostate carcinoma. Of the eligible cases (n=40), there were 9 high-grade urothelial carcinomas, 27 prostate carcinomas and 4 with both prostate and bladder tumours. All diagnoses were made by integrating the clinical, radiological, morphological and IHC results.

RESULTS

In all the prostate carcinomas, there was diffuse, intense nuclear staining for AR. The urothelial tumours were either negative, had cytoplasmic staining or showed occasionally weak nuclear staining. The difference was highly significant with p<0.0001 (Mann-Whitney U test).

CONCLUSIONS

We conclude that AR is an important marker as it is best able to distinguish between poorly differentiated urothelial and prostate carcinoma. AR appears superior to PSA and PSAP, which are not consistently expressed in high-grade prostate carcinoma. Also, high-grade urothelial carcinoma may be negative for CK20, p63/HMWK and occasionally CK7. We advocate the inclusion of AR in the panel of markers to differentiate these tumours.

Utility of GATA3 immunohistochemistry in differentiating urothelial carcinoma from prostate adenocarcinoma and squamous cell carcinomas of the uterine cervix, anus, and lung

Distinguishing invasive high-grade urothelial carcinoma (UC) from other carcinomas occurring in the genitourinary tract may be difficult. The differential diagnosis includes high-grade prostatic adenocarcinoma, spread from an anal squamous cell carcinoma (SCC), or spread from a uterine cervical SCC. In terms of metastatic UC, the most common problem is differentiating spread of UC to the lung from a primary pulmonary SCC. Immunohistochemical analysis (IHC) for GATA binding protein 3 (GATA3), thrombomodulin (THROMBO), and uroplakin III was performed on a tissue microarray (TMA) containing 35 cases of invasive high-grade UC. GATA3 IHC was also performed on TMAs containing 38 high-grade (Gleason score ≥8) prostatic adenocarcinomas, representative tissue sections from 15 invasive anal SCCs, representative tissue sections from 19 invasive cervical SCCs, and TMAs with 12 invasive cervical carcinomas of the cervix [SCC (n=10), SCC with neuroendocrine features (n=1), and adenosquamous carcinoma (n=1)]. In addition, GATA3 IHC was performed on representative tissue sections from 15 pulmonary UC metastases and a TMA with 25 SCCs of the lung and 5 pulmonary non-small cell carcinomas with squamous features. GATA3, THROMBO, and uroplakin III were positive in 28 (80%), 22 (63%), and 21 (60%) cases of high-grade UC, respectively. All cases of GATA3-positive staining were nonfocal; 25 (89%) cases demonstrated moderate to strong staining, and 3 (11%) demonstrated weak staining. Of the 7 cases that failed to express GATA3, 5 were positive for THROMBO and/or uroplakin III, whereas 2 were negative for all 3 markers. None of the 38 high-grade prostatic adenocarcinomas was positive for GATA3. Weak GATA3 staining was present in occasional basal cells of benign prostate glands, in a few benign atrophic glands, and in urothelial metaplasia. Of the 15 cases of anal SCCs, 2 (7%) cases showed focal weak staining, and 1 (3%) showed focal moderate staining. Weak staining was also rarely observed in the benign anal squamous epithelium. Of the 31 uterine cervical carcinomas, 6 (19%) showed weak GATA3 staining (3 nonfocal and 3 focal), and 2 (6%) demonstrated focal moderate staining. Twelve (80%) of the metastatic UCs to the lung were positive for GATA3, with 11 cases showing diffuse moderate or strong staining and 1 case showing focal moderate staining. None of the pulmonary SCCs or non-small cell carcinomas with squamous features was GATA3 positive. GATA3 IHC is a sensitive marker for UC, and positive staining in UC is typically nonfocal and moderate or strong in intensity. GATA3 is also highly specific in excluding high-grade prostate adenocarcinoma. Although some cervical and anal SCCs can be GATA3 positive, unlike in UC, staining is more commonly focal and weak. GATA3 is also a useful maker when diagnosing metastatic UC to the lung.

Expression of cytokeratin 34βE12 is a good indicator of tumor progression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is considered one of the most aggressive cancers with poor prognosis. The high molecular weight cytokeratin 34βE12 (CK34βE12) is recognized by the antibody, that is expressed in the cytoplasm of epithelial basal cells, and has been considered as a potential marker for prostate cancer, breast cancer, and basaloid carcinoma of the lung. However, there are no clinicopathological studies investigating CK34βE12 expression at the invasive front of ESCC. In this study, we examined 170 surgically resected cases of ESCC to clarify the clinicopathological significance of CK34βE12 expression. CK34βE12 expression was found in 85.3% (145/170) of ESCC cases and was significantly correlated with lymph node metastasis (66.2% [96/145], P = 0.034), depth of tumor invasion (57.9% [84/145], P = 0.042), and differentiation (82.1% [119/145], P = 0.013). These results indicated that CK34βE12 expression is a good indicator of lymph node metastasis, depth of tumor invasion, and differentiation in case of ESCC.

Diagnostic utility of p63/P501S double sequential immunohistochemical staining in differentiating urothelial carcinoma from prostate carcinoma

Background

Distinguishing urothelial carcinoma (UC) from prostate carcinoma (PC) is important due to potential therapeutic and prognostic implications. However, this can be a diagnostic challenge when there is limited tissue and in poorly differentiated tumors. We evaluated the diagnostic utility of a dual immunohistochemical stain comprising p63 and P501S (prostein), applied sequentially on a single slide and visualized by double chromogen reaction, in differentiating these two cancers. Thus far, there have been no previous studies assessing the diagnostic utility of p63 and P501S combined together as a dual immunostain in distinguishing between these two cancers.

Methods

p63/P501S dual-color sequential immunohistochemical staining was performed on archival material from 132 patients with high-grade UC and 23 patients with PC, and evaluated for p63 (brown nuclear) and P501S (red cytoplasmic) expression. Both the staining intensity and percentage of positive tumor cells were assessed.

Results

p63 was positive in 119/132 of UC and negative in PC. P501S was positive in 22/23 of PC and negative in UC. The p63+/P501S- immunoprofile had 90% sensitivity and 100% specificity for UC. The p63-/P501S+ immunoprofile had 96% sensitivity and 100% specificity for PC.

Conclusion

Our results indicate that double sequential immunohistochemical staining with p63 and P501S is highly specific and can be a useful tool in distinguishing UC from PC especially when there is limited diagnostic tissue as it can be performed on a single slide.

Expression of vimentin and high-molecular-weight cytokeratin (clone 34ßE12) in differentiating reactive renal tubular cells from low-grade urothelial carcinoma cells in voided urine

OBJECTIVE

Reactive renal tubular cells show features of an atypical repair reaction. Differentiation between reactive renal tubular cells and low-grade urothelial carcinoma (LG-UC) cells can therefore be a diagnostic challenge based on morphology alone. In this study, we evaluated the diagnostic utility of vimentin and a high-molecular-weight cytokeratin antibody (clone 34ßE12) in differentiating reactive renal tubular cells from LG-UC.

METHODS

We evaluated voided urine cytology and surgical specimens from 40 patients with renal disease, and 17 patients with LG-UC. All slides were stained with vimentin and 34ßE12.

RESULTS

In the reactive renal tubular cells in voided urine cytology, vimentin showed strong cytoplasmic staining in 39/40 (97.5%) cases, but all were negative for 34ßE12. LG-UC cells showed positive staining for 34ßE12 in 3/17 (17.6%) cases, whereas none were positivity for vimentin. The reactive renal tubular cells of histological specimens in the renal disease group demonstrated positive for vimentin in all 40 cases and all were negative for 34ßE12. The LG-UC group showed abnormal staining for 34ßE12 in 4/17 (23.5%) cases, whereas none were positive for vimentin.

CONCLUSIONS

Vimentin expression in urine cytology can help to distinguish reactive renal tubular cells from LG-UC. However, 34ßE12 does not appear to be a useful adjunct to distinguish these two groups in voided urine cytology.

Angiosarcoma-like metastatic carcinoma of the liver

Two cases of metastatic carcinoma strikingly simulating angiosarcoma in the liver are described. The first case was a 53-year-old female with cystic liver tumors which were found 22 months after surgery for ureteral cancer. The second case was an 81-year-old female with multiple tumors in the liver and the pancreas, and a post-mortem examination was carried out. She had undergone surgery for skin cancer three years before. Both cases had an angiosarcoma-like appearance macroscopically and microscopically. Immunohistochemically, the tumor cells of both cases were negative for CD31, CD34, and Factor VIII-related antigen and positive for several types of cytokeratin, suggesting that they were not angiosarcomas but carcinomas. Angiosarcoma is the most common sarcoma arising in the liver. Thus, metastatic carcinoma, which resembles angiosarcoma, might be mistaken for angiosarcoma.

Secondary neoplasms of the urinary system and male genital organs

BACKGROUND AND AIMS

In this review we discuss those secondary tumours involving the urinary system and male genital organs that can pose differential diagnostic difficulties with primary lesions, and highlight morphological and ancillary features that could be helpful in reaching a proper assignment of primary origin.

MATERIALS AND METHODS

Based on MEDLINE database searches all reports of secondary tumours involving the urinary system (kidney and bladder) and male genital organs (prostate, testis and penis) were examined.

RESULTS AND DISCUSSION

Involvement by a secondary tumour occurs either as a metastasis or by direct extension. Among non-genitourinary primary sites, colorectal, pulmonary, skin (melanoma) and breast are the most common contributors. Secondary spread from a genitourinary site primary tumour to another genitourinary organ occurs most frequently between the prostate and urinary bladder, given the intimate topographic proximity of the two. The prognosis is very poor, as the secondary tumour usually occurs in patients with carcinoma in the late stages. Few secondary tumours have distinctive histological and immunohistochemical features, making it difficult to make the appropriate diagnosis. Hence, knowledge of the history and clinical setting are particularly important in these cases.

CONCLUSION

The urinary system and male genital organs are not common sites for secondary tumours. They often go either undiagnosed or misdiagnosed in the clinical follow-up of patients with cancer. Accurate diagnosis is essential because of differing therapeutic approaches compared with a primary neoplasm.

Diagnostic problems in the subtyping of renal tumors encountered by five pathologists

The diagnostic problems in the subtyping of renal tumors were evaluated by a panel of five pathologists studying a set of selected tumors. Five pathologists independently assessed a single hematoxylin-and-eosin (HE)-stained slide from 28 selected renal tumors. After this independent assessment, the pathologists reevaluated and discussed all discordant cases. Additional HE-stained sections and immunohistochemically (IHC) stained slides were available. The generalized kappa for interobserver agreement was calculated. After independent assessment of the HE-stained slides, the five pathologists unanimously reached an agreement in the decision between malignant and benign in 82% of the cases. Fifty percent of the cases were correctly subclassified. The overall generalized kappa value for the five pathologists was 0.320 (CI 95% 0.090-0.551), which is considered a moderate agreement. A 100% agreement was reached for all 28 cases after examination of more slides from different tumor areas and IHC-stained sections. An accurate histologic distinction between benign and malignant renal tumors is possible on one HE-stained section. Correct assignment of the subtype is difficult on one slide alone and relies on IHC-markers and additional slides. Tumors composed of an eosinophilic cell type and tumors with a papillary growth pattern were the major causes of an incorrect diagnosis on an HE-stained section alone.

Immunohistochemical differentiation of high-grade prostate carcinoma from urothelial carcinoma

The histologic distinction between high-grade prostate cancer and infiltrating high-grade urothelial cancer may be difficult, and has significant implications because each disease may be treated very differently (ie, hormone therapy for prostate cancer and chemotherapy for urothelial cancer). Immunohistochemistry of novel and established prostatic and urothelial markers using tissue microarrays (TMAs) were studied. Prostatic markers studied included: prostate-specific antigen (PSA), prostein (P501s), prostate-specific membrane antigen (PSMA), NKX3.1 (an androgen-related tumor suppressor gene), and proPSA (pPSA) (precursor form of PSA). "Urothelial markers" included high molecular weight cytokeratin (HMWCK), p63, thrombomodulin, and S100P (placental S100). TMAs contained 38 poorly differentiated prostate cancers [Gleason score 8 (n=2), Gleason score 9 (n=18), Gleason score 10 (n=18)] and 35 high-grade invasive urothelial carcinomas from radical prostatectomy and cystectomy specimens, respectively. Each case had 2 to 8 tissue spots (0.6-mm diameter). If all spots for a case showed negative staining, the case was called negative. The sensitivities for labeling prostate cancers were PSA (97.4%), P501S (100%), PSMA (92.1%), NKX3.1 (94.7%), and pPSA (94.7%). Because of PSA's high sensitivity on the TMA, we chose 41 additional poorly differentiated primary (N=36) and metastatic (N=5) prostate carcinomas which showed variable PSA staining at the time of diagnosis and performed immunohistochemistry on routine tissue sections. Compared to PSA, which on average showed 18.8% of cells with moderate to strong positivity, cases stained for P501S, PSMA, and NKX3.1 had on average 42.5%, 53.7%, 52.9% immunoreactivity, respectively. All prostatic markers showed excellent specificity. HMWCK, p63, thrombomodulin, and S100P showed lower sensitivities in labeling high-grade invasive urothelial cancer in the TMAs with 91.4%, 82.9%, 68.6%, and 71.4% staining, respectively. These urothelial markers were relatively specific with only a few prostate cancers showing scattered (<or=2%) weak-moderate positive cells. In summary, PSA can be used as the first screening marker for differentiating high-grade prostate adenocarcinoma from high-grade urothelial carcinoma. Immunohistochemistry for P501S, PSMA, NKX3.1, and pPSA are useful when high-grade prostate cancer is suspected based on the morphology or clinical findings, yet shows negative or equivocal PSA staining. HMWCK and p63 are superior to the novel markers thrombomodulin and S100P.

Immunohistochemical markers in urinary bladder carcinomas from paraffin-embedded archival tissue after storage for 5-70 years

OBJECTIVE

To evaluate archival tissue specimens from bladder tumours and seek molecular changes in samples collected over seven decades previously, as although the frequencies of some cancer types have remained stable during the last 50 years, the incidence of others, including bladder tumours, has increased significantly, and molecular analyses of bladder cancer over periods with an increasing incidence are of interest as the findings might reflect varying external influences.

MATERIALS AND METHODS

Immunohistochemical staining with the biological markers p53 protein, p16 protein, epidermal growth factor receptor (EGFR), cytokeratin 7 and high molecular weight 34betaE12 cytokeratin (HMW-cytokeratin, characteristic of basal cells) was used on archival, paraffin wax-embedded autopsy/biopsy tissue material collected from 144 patients with invasive bladder cancer (World Health Organisation grade II and III). The cases were selected from the periods 1932-48, 1950-59, 1960-70 and 1990-2004. Control immunohistochemistry was done on available normal tissue (i.e. connective and fatty tissue, heart, lungs and normal urinary bladder epithelium) obtained from the autopsies.

RESULTS

The normal tissues were all largely negative for EGFR, had <1% positively stained nuclei for p53 and strong positive reactions for p16, and in epithelial tissues the two cytokeratins were detected. The positive scores for HMW-cytokeratin in the tumour tissue decreased significantly from approximately 90% to 30% over the 70 years. For p53 there was a higher fraction of positive scores (borderline significant) with time. The p16-positive tumours showed no significant variation, with the highest frequency of positive scores in recent years. Overexpression of EGFR in the tumours was significantly correlated with the occurrence of HMW-cytokeratin and decreased from approximately 85% to 65% (not significant), with the lowest frequency in the samples from 1990 to 2004. Autolysis after death or long storage periods did not compromise good quality in the histochemical analyses of the autopsy tissue.

CONCLUSION

The higher frequency of HMW-cytokeratin, lower p53 accumulation and more EGFR expression in grade II and III urinary bladder carcinomas from the 1930s could indicate different phenotypes in bladder cancer during this 70-year period. The successful detection of these protein markers in old archival material allows larger retrospective studies that might increase the understanding of molecular carcinogenesis in bladder cancer.

Poorly differentiated adenocarcinomas of prostate versus high-grade urothelial carcinoma of the bladder: a diagnostic dilemma with immunohistochemical evaluation of 2 cases

The differential diagnosis between carcinoma of the urinary bladder and adenocarcinoma of the prostate can be difficult, especially in the poorly differentiated forms infiltrating the neighboring organs. In this article, the authors report 2 cases that pose a diagnostic dilemma to the pathologist. The first is an infiltration of the bladder by a poorly differentiated adenocarcinoma of the prostate, which was clinically suspected as a papillary urothelial neoplasm. The second is a collision tumor composed of prostatic adenocarcinoma and urothelial carcinoma observed on a core needle biopsy of the prostate. In both cases, a large panel of immunohistochemical markers were used and demonstrated positivity for prostate-specific antigen and alpha methyl racemase in the prostatic carcinomas and immunoreactivity for CK7, CK20, Ag 34betaE12, and p53 in the urothelial carcinoma. The differentiating histological and immunohistochemical findings are discussed.

Prostate-specific antigen, high-molecular-weight cytokeratin (clone 34betaE12), and/or p63: an optimal immunohistochemical panel to distinguish poorly differentiated prostate adenocarcinoma from urothelial carcinoma

An optimal immunohistochemical panel to distinguish poorly differentiated prostate (PCa) from urothelial (UCa) carcinoma was selected from a panel consisting of prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP), high-molecular-weight cytokeratin (HMWCK), clone 34betaE12, cytokeratin (CK) 7, CK20, p63, and alpha-methylacyl-coenzyme A racemase. The pilot group was composed of poorly differentiated UCa (n = 36) and PCa (n = 42). PSA and PAP stained 95% of PCa vs 0% and 11% of UCa cases, respectively. HMWCK and p63 stained 97% and 92% of UCa vs 2% and 0% of PCa cases respectively. CK7/CK20 coexpression was noted in 50% of UCa cases, whereas 86% of PCa cases were negative with both. A panel of PSA, HMWCK, and p63 was optimal for separating 95% PCa (PSA+/HMWCK and/or p63-) vs 97% UCa (PSA-/HMWCK and/or p63+). This panel was used on 26 diagnostically challenging cases and resolved 81% of cases as UCa vs PCa. The majority of PCa cases retain PSA. Negative PSA with positive HMWCK and/or p63 establishes a diagnosis of UCa.

An immunohistochemical approach to the differential diagnosis of renal tumors

Renal neoplasms comprise several distinct clinicopathologic entities with potential prognostic and the rapeutic differences. Although careful morphologic examination using sections stained with hematoxylin and eosin will allow for the correct diagnosis in the majority of cases, there is sufficient overlap between several entities such that ancillary techniques may be necessary to arrive at the correct diagnosis. In routine diagnostic surgical pathology practice of renal tumors, immunohistochemistry is the foremost ancillary technique. Using an approach based on common histologic patterns (tumors with clear cytoplasm, granular cytoplasm, tubulopapillary architecture, spindle cell morphology, small round-cell morphology, and infiltrating poorly differentiated carcinoma), we will discuss the utility of immunohistochemistry in the differential diagnosis of renal neoplasms. In recent years, needle biopsies from renal masses are being increasingly performed. In these small biopsies, the entire range of cytoarchitectural features that are generally necessary to make a diagnosis may not be fully appreciated. Immunohistochemistry may be helpful in this setting to narrow the differential diagnosis or to arrive at a definitive diagnosis. Finally, the use of immunohistochemistry for the confirmation of metastatic renal cell carcinoma presenting at distant sites will be discussed. Panels of immunohistochemical stains are proposed for different settings, including renal cell carcinoma (RCC) marker, CD10, and vimentin to suggest renal origin of a metastatic tumor, and markers to aid in subclassification of RCC, including parvalbumin and c-kit for chromophobe RCC, and cytokeratin 7 and alpha-methyl-acyl-CoA racemase for papillary RCC.

Effect of terazosin on tissue vascularity and apoptosis in transitional cell carcinoma of bladder

OBJECTIVES

To present a pilot study to determine whether the alpha1-adrenoceptor antagonist terazosin can induce apoptosis in transitional cell carcinoma (TCC) of the bladder, similar to the effect seen with prostate cancer. The alpha1-adrenoceptor antagonist terazosin has recently been shown to induce apoptosis in prostate cancer cells both in vitro and in vivo and to reduce prostatic tissue vascularity by potentially affecting endothelial cell adhesion.

METHODS

The records of 24 men who underwent radical cystectomy for TCC of the bladder at the Lexington Veterans Affairs Medical Center were reviewed. The control group consisted of 15 men who were never exposed to terazosin. The study group consisted of 9 men who were treated with terazosin before cystectomy. Sections of the bladder tumor and normal trigone were subjected to immunohistochemical analysis for microvessel density, endothelial cell CD31 expression, and apoptosis detection (terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling), as well as high-molecular-weight cytokeratin staining.

RESULTS

A significant reduction in tissue vascularity (14.0 versus 19.2, P <0.05) and a significant increase in the apoptotic index (3.0% versus 1.7%, P <0.05) was detected in terazosin-treated bladder tumors compared with untreated bladder tumors. Most TCC specimens (80%) exhibited strong and consistently uniform immunostaining for high-molecular-weight cytokeratin staining.

CONCLUSIONS

These results suggest that terazosin reduces tumor vascularity and induces apoptosis in TCC of the bladder. Additional studies with more patients are necessary to reach definitive conclusions. However, considering the proven apoptotic action of terazosin in prostatic tissue, this study may have implications for the use of terazosin in the treatment of bladder TCC.

PSGR2, a novel G-protein coupled receptor, is overexpressed in human prostate cancer

The G-protein coupled receptors (GPCRs) recognize a large variety of extracellular molecules (such as hormones, neurotransmitters, growth and developmental factors) and several sensory messages (such as light, odors and pain). GPCRs and their signal transduction pathway represent important specific targets for a variety of human diseases. To investigate the potential roles of GPCRs in human normal prostate and prostate cancers, we identified and characterized a novel human G-protein coupled receptor, PSGR2, which is highly overexpressed in human prostate cancers. Although PSGR2 shares sequence homology with human olfactory G-protein coupled receptors, the expression of PSGR2 is highly restricted to human prostate tissue, and no expression was detected in 22 normal and 10 tumor tissues examined using Northern blot and PCR analysis. Furthermore, we investigated the expression levels of PSGR2 in 133 human prostate samples with real-time quantitative reverse transcription-PCR and in situ hybridization method. We demonstrated that PSGR2 expression increased significantly in human high grade prostate intraepithelial neoplasia (PIN) and prostate cancers (approximately 10-fold) as compared to normal and BPH (benign prostatic hyperplasia) tissues (p < 0.001), suggesting PSGR2 may play an important role in human prostate cancer development and progression. Together, our results suggest that PSGR2 is a novel prostate specific G-protein coupled receptor and may be useful as a tissue marker and molecular target for the early detection and treatment of human prostate cancers.

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.

Tumour markers for managing men who present with metastatic prostate cancer and serum prostate-specific antigen levels of <10 ng/mL

OBJECTIVE

To define immunohistochemical features of the primary cancers that might help in the differential diagnosis and monitoring of treatment in men presenting with metastatic prostate cancer and low serum levels of prostate-specific antigen (PSA), who can be difficult to diagnose and manage.

PATIENTS AND METHODS

Paraffin blocks of prostate biopsies were obtained for 33 patients presenting with untreated metastatic prostate cancer and serum PSA levels of <10 ng/mL. Sections were immunostained for PSA, prostatic acid phosphatase (PAP), prostate-specific membrane antigen (PSMA), androgen receptor (AR), chromogranin A and CD 56.

RESULTS

The combined Gleason scores were 8-10 in 25 men (76%) and 6 or 7 in the other eight (24%). Morphologically, there were no neuroendocrine features. PSA immunostaining was equivocal in 12 (36%) cases and in a further 19 (58%) was strong but focal and could be missed on biopsy sampling. PSMA was expressed in 90% of cases, and staining was widely distributed in nine of the 12 in which PSA staining was equivocal. There was strong AR expression in 30 (91%) cases and it was present in areas where PSA was absent.

CONCLUSION

In this patient group, immunohistochemical assessments of PSMA and AR are potentially useful as diagnostic markers.

The role of immunohistochemistry in the diagnosis of urinary bladder neoplasms

The spectrum of neoplasms involving the urinary bladder is diverse, and, at times, different entities with distinct prognostic and managerial implications may have significant morphologic overlap. The presence of a neoplasm with an unusual morphologic appearance, such as an undifferentiated spindled, or plasmacytoid pattern may necessitate immunohistochemistry to establish the diagnosis. In this review, we discuss a series of distinct diagnostic scenarios, including high-grade undifferentiated carcinoma versus prostatic adenocarcinoma, enteric-type adenocarcinoma versus secondary colorectal adenocarcinoma, spindle cell proliferations, neoplasms with plasmacytoid morphology, endophytic tumors with a nested growth pattern, and flat urothelial lesions with atypia. We also discuss markers supporting urothelial differentiation in the context of a metastatic carcinoma from an unknown primary. The importance of using a morphologically derived differential diagnosis to guide the selection and interpretation of immunohistochemical studies is emphasized, and the varying utility (specificity) of the individual immunohistochemical markers within each setting is addressed.

Immunohistochemistry in diagnostic surgical pathology of the prostate

Immunohistochemistry (IHC) can play an important role in diagnostic surgical pathology of the prostate. Basal cell markers, such as the 34betaE12 antibody and antibodies directed against cytokeratin 5 and 6 or p63, are very useful for demonstration of basal cells as their presence argues against a diagnosis of invasive prostatic carcinoma (PC). However, several benign mimickers of PC, including atrophy, atypical adenomatous hyperplasia (AAH), nephrogenic adenoma, and mesonephric hyperplasia, can stain negatively with these markers, and thus, a negative basal cell marker immunostain alone does not exclude a diagnosis of benignancy. Although there are examples in the literature of high grade PC that stain focally with some of the basal cell markers, these cases are usually readily diagnosed based on H&E appearances and are unlikely to be confused with these benign mimickers. Alpha-methylacyl-coenzyme-A racemase (AMACR) is a sensitive marker of PC (except for a few uncommon variants: atrophic, foamy gland, and pseudohyperplastic variants), and its detection by immunohistochemical staining in atypical prostatic lesions can be very useful in confirming an impression of adenocarcinoma. AMACR expression can also be identified in high grade prostatic intraepithelial neoplasia (PIN), prostatic atrophy, AAH, and benign prostatic glands, and accordingly, a diagnosis of PC should not be based solely on a positive AMACR immunostain, especially when the luminal staining is weak and/or noncircumferential. The use of AMACR/basal cell antibody cocktails has been found to greatly facilitate the distinction between PC and its benign mimickers, especially when only limited tissue is available for staining. Prostate specific antigen (PSA) and prostate specific acid phosphatase (PSAP) are both quite sensitive and fairly specific markers of PC (there are a few nonprostatic tumors that can express one or both), and are both very helpful in establishing or confirming the diagnosis of PC when the differential diagnosis includes other tumors that can involve the prostate such as urinary bladder urothelial carcinoma. 34betaE12, p63, thrombomodulin, and uroplakin III are additional urothelial associated markers useful in this differential diagnosis. CDX2 and villin are useful markers to diagnostically separate colonic adenocarcinoma from PC. AMACR positivity and negative basal cell marker reactions are useful to confirm the presence of residual PC after hormonal or radiation therapy. Pan-cytokeratin, PSA, and PSAP can also highlight subtle infiltrates of PC with hormonal or radiation therapy effect. PSA and PSAP immunohistochemical stains are valuable in confirming metastatic carcinoma as being of prostatic origin and should always be utilized in the diagnostic evaluation of metastatic adenocarcinoma of unknown primary origin in males.