Histogenesis of clear cell adenocarcinoma in the urinary tract: evidence of urothelial origin

Diagnostic Approach to and Differential Diagnosis of Clear Cell and Glandular Lesions of the Lower Urinary Tract

CONTEXT.—

A variety of glandular and clear cell lesions may be seen in the urinary bladder and/or urethra, ranging from benign to malignant primary and secondary tumors. Lesions with no malignant potential include reactive processes, such as nephrogenic metaplasia, and may show similar morphologic features as an infiltrative neoplasm, particularly in small biopsies. Similarly, ectopic tissues of Müllerian origin may be seen in the lower urinary tract, and their distinction from a true glandular neoplasm is essential to avoid overtreatment. A wide variety of primary and secondary malignant tumors exist with varying degrees of glandular and clear cell features. Therefore, surgical pathologists must be aware of the full scope of possible lesions to avoid misdiagnosis.

OBJECTIVE.—

To provide a practical framework for approaching the diagnosis of clear cell and glandular lesions of the urinary bladder/urethra and prostate, highlighting the strengths and limitations of various diagnostic features and ancillary tests.

DATA SOURCES.—

A review of the current literature was performed to obtain data regarding up-to-date diagnostic features and ancillary studies.

CONCLUSIONS.—

In summary, distinct morphologic and immunohistochemical features and clinical and radiologic correlation are essential to establish an accurate diagnosis when such cases with glandular and clear features are encountered in the lower urinary tract.

Clear Cell Adenocarcinoma of Urethra: Clinical and Pathologic Implications and Characterization of Molecular Aberrations

PURPOSE

This study aimed to evaluate the molecular features of clear cell adenocarcinoma (CCA) of the urinary tract and investigate its pathogenic pathways and possible actionable targets.

MATERIALS AND METHODS

We retrospectively collected the data of patients with CCA between January 1999 and December 2016; the data were independently reviewed by two pathologists. We selected five cases of urinary CCA, based on the clinicopathological features. We analyzed these five cases by whole exome sequencing (WES) and subsequent bioinformatics analyses to determine the mutational spectrum and possible pathogenic pathways.

RESULTS

All patients were female with a median age of 62 years. All tumors were located in the urethra and showed aggressive behavior with disease progression. WES revealed several genetic alterations, including driver gene mutations (AMER1, ARID1A, CHD4, KMT2D, KRAS, PBRM1, and PIK3R1) and mutations in other important genes with tumor-suppressive and oncogenic roles (CSMD3, KEAP1, SMARCA4, and CACNA1D). We suggest putative pathogenic pathways (chromatin remodeling pathway, mitogen-activated protein kinase signaling pathway, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin pathway, and Wnt/β-catenin pathway) as candidates for targeted therapies.

CONCLUSION

Our findings shed light on the molecular background of this extremely rare tumor with poor prognosis and can help improve treatment options.

A Rare Case of Primary Clear Cell Adenocarcinoma of the Urinary Bladder

Adenocarcinoma is a rare form of urinary bladder cancer, comprising only 2% of cases, with various histological patterns and levels of differentiation. Among these, clear cell adenocarcinoma is the least common. Contrary to other subtypes, clear cell adenocarcinoma of the bladder has been shown to have a female predominance, and typically presents at the age of 60 after being incidentally discovered on radiological and urinary studies. However, signs and symptoms such as visible and non-visible hematuria, and signs and symptoms of urinary tract infection refractory to antibiotic treatment could occur and clue into the diagnosis. Although imaging can reveal and characterise the lesion, definitive diagnosis requires cystoscopy with biopsy. The treatment of adenocarcinoma of the bladder often requires surgical resection, with adjuvant chemotherapy being utilized in a subset of patients. We report a 79-year-old patient complaining of gross hematuria. Ultrasound was performed and showed a calcified mass at the dome of the urinary bladder, which was confirmed by computerized tomography of the abdomen and pelvis. Subsequent cystoscopy confirmed the diagnosis of clear-cell adenocarcinoma and the tumor was resected using a trans-urethral approach. Radical cystectomy with regional lymphadenectomy and adjuvant chemotherapy were used as the primary therapeutic modality.

Single-cell RNA sequencing reveals the immune microenvironment and signaling networks in cystitis glandularis

Introduction

Cystitis glandularis (CG) is a rare chronic bladder hyperplastic disease that mainly manifests by recurrent frequent urination, dysuria and gross hematuria. The current lack of unified diagnosis and treatment criteria makes it essential to comprehensively describe the inflammatory immune environment in CG research.

Methods

Here, we performed scRNA-sequencing in CG patients for the first time, in which four inflamed tissues as well as three surrounding normal bladder mucosa tissues were included. Specifically, we isolated 18,869 cells to conduct bioinformatic analysis and performed immunofluorescence experiments.

Results

Our genetic results demonstrate that CG does not have the classic chromosomal variation observed in bladder tumors, reveal the specific effects of TNF in KRT15 epithelial cells, and identify a new population of PIGR epithelial cells with high immunogenicity. In addition, we confirmed the activation difference of various kinds of T cells during chronic bladder inflammation and discovered a new group of CD27-Switch memory B cells expressing a variety of immunoglobulins.

Discussion

CG was regarded as a rare disease and its basic study is still weak.Our study reveals, for the first time, the different kinds of cell subgroups in CG and provides the necessary basis for the clinical treatment of cystitis glandularis. Besides, our study significantly advances the research on cystitis glandularis at the cellular level and provides a theoretical basis for the future treatment of cystitis glandularis.

Urothelial Carcinoma: Divergent Differentiation and Morphologic Subtypes

Urothelial carcinoma (UC) is known to encompass a wide spectrum of morphologic features and molecular alterations. Approximately 15% to 25% of invasive UC exhibits histomorphologic features in the form of "divergent differentiation" along other epithelial lineages, or different "subtypes" of urothelial or sarcomatoid differentiation. It is recommended that the percentage of divergent differentiation and or subtype(s) be reported whenever possible. Recent advances in molecular biology have led to a better understanding of the molecular underpinning of these morphologic variations. In this review, we highlight histologic characteristics of the divergent differentiation and subtypes recognized by the latest version of WHO classification, with updates on their molecular and clinical features.

GATA3 expression in clear cell adenocarcinoma of the lower urinary tract: a potential diagnostic pitfall

BACKGROUND

Clear cell adenocarcinoma of the lower urinary tract (CCACLUT) is a rare primary malignant neoplasm with heterogenous morphology. There is a paucity of data in the literature regarding its immunohistochemical profile.

METHODS

The immunohistochemical features (extent and intensity) of a multinational cohort of CCACLUT were evaluated with comparison between clear cell adenocarcinoma of the female genital tract (CCACFGT, tissue microarray) and nephrogenic adenoma (NA).

RESULTS

33 CCACLUT (24 female, 9 male; mean age 59 years) were collected. CCACLUT most commonly arose from the urinary bladder (26/33, 78%), particularly from the trigone (10/33, 30.3%) followed by the urethra (8/33, 22%). All 12 NA cases were located at the urinary bladder, whereas the most common CCACFGT location was the ovary (29/56, 52%). None of the CCACLUT patients had, intestinal metaplasia, NA, or urothelial carcinoma. One patient had concurrent endometriosis of the sigmoid colon. Most frequently observed morphology in CCACLUT was papillary/tubulocystic (9/3; 27.3%), followed by papillary/tubular (6/33; 18.2%) and papillary/solid (5/33; 15.2%). GATA3 expression was significantly higher in CCACLUT (18/33, 54.5%) and NA (6/12, 50%), when compared to CCACFGT cases 6/56, 11.7%)(p = 0.001 and p = 0.022, respectively). The extent of GATA3 was significantly higher in CCACLUT group (19.2 ± 16.6%) than the other groups (9.6 ± 22.5% in NA and 2.6 ± 9% in CCACFGT group) (p = 0.001). 4/33 patients (12.1) had weak, 10/33 patients (30.3%) had moderate, and 4/33 patients (12.1%) had strong GATA3 intensity in CCACLUT group. In NA group, one patient (8.3%, 1/12) had weak, one patient (8.3%, 1/12) had moderate and 4 patients (33.3%, 4/12) had strong GATA3 intensity. Most cases (CCACLUT 29/33, 88%; NA 11/12, 92%; CCACFGT 46/56, 82.1%) had positive Napsin A expression, by which CCACLUT had significantly more cases with Napsin A expression (p = 0.034). p63 was consistently negative in all cases (30/33 (91.9%) CCACLUT; 12/12 (100%) NA; 42/56 (75%) CCACFGT. Ki67 (MIB) proliferation index was significantly higher in CCACLUT group (54.6 ± 21%) when compared to NA group (4.5 ± 2.7%) and CCACFGT group (35.5 ± 25.8%) (p = 0.001).

CONCLUSION

CCACLUT has consistent GATA3 expression, which may cause challenge in the diagnosis of urothelial carcinoma but can be used to distinguish CCACLUT from CCACFGT.

Clear Cell Adenocarcinoma in Men: A Series of 15 Cases

Clear cell adenocarcinoma (CCA) is a rare tumor in the genitourinary tract with female predominance and few reports in men. We identified 15 cases of CCA in men evaluated at our institution. Five arose in the bladder, 7 in the prostate or prostatic urethra, 2 in the membranous urethra (1 multifocal in the prostatic and membranous urethra), 1 periprostatic (likely from an embryologic remnant), and 1 between rectum and bladder (likely in a prostatic utricle cyst). No cases showed associated Müllerian structures. One case showed separate foci of nephrogenic adenoma at diagnosis, and 1 case showed urothelial carcinoma in situ on a later follow-up biopsy. Four tumors extended into other organs (prostate to seminal vesicle and periprostatic soft tissue, periprostatic soft tissue to prostate, prostatic urethra to bladder and rectum, and prostate to bladder neck). One tumor showed extraprostatic extension alone. Four tumors metastasized to lymph nodes, with 3 also metastasizing to other sites (bladder, lung and adrenal, and right flank). Eleven patients underwent resection, including 3 transurethral resections. Seven underwent other treatments, including radiation (5 [1 for recurrence]), chemotherapy (3), hormonal therapy (3), immunotherapy with nivolumab (1), and targeted therapy with gefitinib (1). The mean follow-up was 35 months (range: 1 to 138 mo). At the last follow-up, 7 patients showed no evident disease and 3 were alive with disease. Four died with the cause of death unknown, with 2 cases having confirmed disease at the time of death and the remaining 2 dying less than a year after diagnosis. The mean time to death was 16 months (range: 6 to 39 mo). No follow-up was available on 1 patient. All patients who died in this series had CCA of the prostate or prostatic urethra. Pathologists need to be attuned to CCA occurring in males, given that the literature emphasizes its occurrence in females. In addition to established sites such as bladder and urethra, our series demonstrates that tumor may present in unusual adjacent sites, such as in periprostatic embryologic remnants or prostatic utricle.

Clear cell carcinoma of the urinary bladder: a systematic review

PURPOSE

We conducted a systematic review of the literature on primary clear cell carcinoma (CCC) of the urinary bladder.

METHODS

A literature search using keywords and MeSH terms related to "clear cell carcinoma", "clear cell adenocarcinoma", "mesonephroma" and "urinary bladder" in EMBASE, MEDLINE and Cochrane Central Register of Controlled Trials was performed. A manual search was performed with web-based search engine Google Scholar. Reference lists of the included studies were screened for additional articles. Articles up till 16th July 2020 were retrieved. Observational human studies on primary CCC in urinary bladder with English full-text were included for further analysis.

RESULTS

904 articles were identified and 44 articles were included for further analysis. Data including clinical features, tumour characteristics, treatment and oncological outcomes were reviewed. There were 70 patients (44 females and 26 males) reported in literatures and included in this review. Gross haematuria was the most common presentation (79.7%), followed by irritative urinary symptoms (47.5%). Regarding the histology, tubulocystic pattern is the most common histologic pattern (49.1%), and 52.6% had muscle invasion. Most cases were CK7 (96.6%) and CK20 (88.9%) positive. CA125 (96%) was commonly positive, indicating its potential origin from mullerian duct. Most patients received surgery (95.5%) as primary treatment. However, the oncological outcomes were unsatisfactory with a 2-year survival rate of 60.0%.

CONCLUSION

Clear cell carcinoma is an uncommon subtype of bladder cancer which can be diagnosed by histology and immunohistochemical staining result. The majority of patients presented with muscle invasion and had a poor survival despite aggressive treatment.

Clear cell variant, urothelial carcinoma of ureter: A rare entity

Clear cell variants of transitional cell carcinoma of upper urinary tract is extremely rare. Although clear cell of urinary bladder has been reported, its occurrence in the upper tract has not been reported readily in literature.

We present a case of 77 year old female who was suspected with TCC of the ureter, but was found to have clear cell variant on histology post radical nephroureterectomy.

This was the first such case in our institution.

Histologic Variants of Urothelial Carcinoma: Morphology, Molecular Features and Clinical Implications

Bladder cancer is a heterogeneous disease including conventional urothelial carcinoma (UC) and its histologic variants, and non-urothelial carcinoma, including squamous and glandular neoplasms. Urothelial carcinoma accounts for the majority of bladder cancer cases, but morphologic variants are common and include nested, microcystic, micropapillary, lymphoepithelioma-like, plasmacytoid, sarcomatoid, giant cell, undifferentiated, clear cell and lipoid. Certain variants of UC tend to be associated with a poor prognosis and have diagnostic and potential treatment implications that make the identification of variant histology crucial to clinical decision making. While there is still uncertainty regarding the prognostic implications of many of these variants, identifying and reporting variant histology is important to develop our understanding of their biology. Unique molecular features accompany many of these morphologic variants and to better understand these tumors, we review the molecular and clinical implications of histologic variants of bladder cancer. Major efforts are underway to include variant histology and divergent differentiation of UC in clinical trials to develop evidence based approaches to treatment. The purpose of this article is to review the current literature on variant histology of urothelial cancer and to highlight molecular findings and the clinical relevance of these tumors.

Dataset for the reporting of urinary tract carcinoma-biopsy and transurethral resection specimen: recommendations from the International Collaboration on Cancer Reporting (ICCR)

The International Collaboration on Cancer Reporting (ICCR) is an alliance of major pathology organisations in Australasia, Canada, Europe, United Kingdom, and United States of America that develops internationally standardised, evidence-based datasets for the pathology reporting of cancer specimens. This dataset was developed by a multidisciplinary panel of international experts based on previously published ICCR guidelines for the production of cancer datasets. It is composed of Required (core) and Recommended (noncore) elements identified on the basis of literature review and expert consensus. The document also includes an explanatory commentary explaining the rationale behind the categorization of individual data items and provides guidance on how these should be collected and reported. The dataset includes nine required and six recommended elements for the reporting of cancers of the urinary tract in biopsy and transurethral resection (TUR) specimens. The required elements include specimen site, operative procedure, histological tumor type, subtype/variant of urothelial carcinoma, tumor grade, extent of invasion, status of muscularis propria, noninvasive carcinoma, and lymphovascular invasion (LVI). The recommended elements include clinical information, block identification key, extent of T1 disease, associated epithelial lesions, coexistent pathology, and ancillary studies. The dataset provides a structured template for globally harmonized collection of pathology data required for management of patients diagnosed with cancer of the urinary tract in biopsy and TUR specimens. It is expected that this will facilitate international collaboration, reduce duplication of effort in updating current national/institutional datasets, and be particularly useful for countries that have not developed their own datasets.

Dataset for the reporting of carcinoma of the bladder-cystectomy, cystoprostatectomy and diverticulectomy specimens: recommendations from the International Collaboration on Cancer Reporting (ICCR)

The International Collaboration on Cancer Reporting (ICCR) is a not for profit organisation whose goal is to produce standardised internationally agreed and evidence-based datasets for pathology reporting. With input from pathologists worldwide, the datasets are intended to be uniform and structured. They include all items necessary for an objective and accurate pathology report which enables clinicians to apply the best treatment for the patient. This dataset has had input from a multidisciplinary ICCR expert panel. The rationale for some items being required and others recommended is explained, based on the latest literature. The dataset incorporates data from the World Health Organization (WHO) 2016, and also from the latest (8th edition) TNM staging system of the American Joint Committee on Cancer (AJCC). Fifteen required elements and eight recommended items are described. This dataset provides all the details for a precise and valuable pathology report required for patient management and prognostication. This dataset is intended for worldwide use, and should facilitate the collection of standardised comparable data on bladder carcinoma at an international level.

Rare Case of Primary Clear Cell Carcinoma of the Urinary Bladder

Cancers of the urinary bladder account for about 3.2% of all cancers worldwide. Clear cell adenocarcinomas (CCAs) of urinary bladder are rare. CCA must be differentiated from benign condition such as nephrogenic adenoma (NA) as well as malignant conditions such as urothelial carcinoma with clear cells, metastasis from ovary and kidney, and urinary bladder myomelanocytic tumor. The diagnosis is based on characteristic histopathological and immunohistochemical features. We present a rare case of CCA of urinary bladder with aggressive clinical behavior in a 72-year-old female.

Molecular profiling of clear cell adenocarcinoma of the urinary tract

Clear cell adenocarcinoma (CCA) of the urinary tract is a rare type of malignancy whose molecular profiles remain undefined. Here we reported an integrated clinicopathologic and molecular profiling analysis of four cases of clear cell adenocarcinoma arising in the urethra or the bladder. Utilizing a clinically validated 130-gene exon-sequencing assay, we identified recurrent pathogenic PIK3CA (p. E545K) and KRAS (p.G12D) variants in three of four (75%) of the cases. In addition, an APC variant (P.S2310X), a TP53 variant (p.R273C), and a MYC amplification event were identified. The only CCA case without either PIK3CA or KRAS variants has a distinct pathogenesis through BK virus, demonstrated by positive BK virus PCR and SV40 immunohistochemistry. The novel finding of recurrent variants in the PI3K/AKT/mTOR pathway provides not only insights into oncogenesis but also potential clinical therapeutic targets for patients with clear cell adenocarcinoma of the urinary tract.

Non-urothelial carcinomas of the bladder

Non-urothelial carcinomas involving the bladder are uncommon and often diagnostically challenging. These carcinomas may show squamous, adenocarcinomatous or neuroendocrine features, with immunohistochemical stains aiding the diagnosis in only a subset of cases. The clinical history in non-urothelial bladder carcinomas is important, given that the differential diagnosis often includes secondary involvement of the bladder by direct extension or metastasis from carcinomas at other sites. This paper will review non-urothelial carcinomas in each of these three morphological categories, emphasising recent changes in diagnostic grouping and challenges in the histopathological diagnosis. Review of bladder cancers with squamous morphology will include discussion of conventional squamous cell carcinoma and verrucous carcinoma and their distinction from urothelial carcinoma with extensive squamous differentiation. Bladder carcinomas with adenocarcinomatous change will include primary bladder adenocarcinoma, urachal adenocarcinoma and tumours of Müllerian type. Finally, neuroendocrine neoplasms of the bladder, including well-differentiated neuroendocrine tumour and neuroendocrine carcinomas, will be discussed. Associated surface findings, risk factors and prognostic features will be described.

Multiclonal tumor origin: Evidence and implications

An accurate understanding of the clonal origins of tumors is critical for designing effective strategies to treat or prevent cancer and for guiding the field of cancer risk assessment. The intent of this review is to summarize evidence of multiclonal tumor origin and, thereby, contest the commonly held assumption of monoclonal tumor origin. This review describes relevant studies of X chromosome inactivation, analyses of tumor heterogeneity using other markers, single cell sequencing, and lineage tracing studies in aggregation chimeras and engineered rodent models. Methods for investigating tumor clonality have an inherent bias against detecting multiclonality. Despite this, multiclonality has been observed within all tumor stages and within 53 different types of tumors. For myeloid tumors, monoclonal tumor origin may be the predominant path to cancer and a monoclonal tumor origin cannot be ruled out for a fraction of other cancer types. Nevertheless, a large body of evidence supports the conclusion that most cancers are multiclonal in origin. Cooperation between different cell types and between clones of cells carrying different genetic and/or epigenetic lesions is discussed, along with how polyclonal tumor origin can be integrated with current perspectives on the genesis of tumors. In order to develop biologically sound and useful approaches to cancer risk assessment and precision medicine, mathematical models of carcinogenesis are needed, which incorporate multiclonal tumor origin and the contributions of spontaneous mutations in conjunction with the selective advantages conferred by particular mutations and combinations of mutations. Adherence to the idea that a growth must develop from a single progenitor cell to be considered neoplastic has outlived its usefulness. Moving forward, explicit examination of tumor clonality, using advanced tools, like lineage tracing models, will provide a strong foundation for future advances in clinical oncology and better training for the next generation of oncologists and pathologists.

Clear cell adenocarcinoma of the bladder with intravesical cervical invasion

A 26-year-old woman with a complicated urological and gynecological history with uterine didelphys with bilaterally inserting intravesical cervical oses presented with cyclical haematuria. Work up revealed a mass in the ectopic cervical os and adjacent bladder wall. Subsequent resection confirmed a clear cell adenocarcinoma of urological origin with invasion into neighbouring os.

Primary Clear Cell Carcinoma of the Urinary Bladder

Primary clear cell carcinoma of the urinary bladder (PCCUB) is rare. Literature review has revealed 47 cases of PCCUB which commonly affects women. The histogenesis of PCCUB is not certain and Müllerian origin and urotheilal origin have been postulated. The microscopic characteristics of PCCUB include cells with abundant clear cytoplasm, arranged in a solid, glandular, tubulocystic, or papillary pattern. The cells may be flat or cuboidal with abundant clear eosinophilic cytoplasm. Hobnailing may be evident. PCCUB, on immunohistochemistry, stain positively with pan-cytokeratin, cytokeratin 7, and CA 125. PCCUB may manifest with visible haematuria, lower urinary tract symptoms, and discharge. There is no consensus opinion regarding the best treatment option for PCCUBs and patient outcomes are not very clear. Surgery has been the adopted treatment of choice. Differential diagnoses of PCCUB include nephrogenic metaplasia, urothelial carcinoma with clear cell cytoplasm, diffuse large B-cell lymphoma, and metastatic clear cell carcinoma with the primary originating elsewhere. Conclusions. A thorough radiological imaging assessment is required in cases of PCCUB to exclude a primary tumour elsewhere. Urologists and oncologists should report cases of PCCUB they encounter and should enter them into a multicentric trial to ascertain the best management option.

Primary urethral clear-cell adenocarcinoma: comprehensive analysis by surgical pathology, cytopathology, and next-generation sequencing

Primary clear-cell adenocarcinoma of the urethra, a rare tumor that histomorphologically resembles clear-cell carcinoma of the female genital tract, occurs predominantly in women and is associated with a relatively poor prognosis. The histogenesis of this rare urethral neoplasm has not been completely resolved, but it is thought to arise from either müllerian rests or metaplastic urothelium. Herein, we present comprehensive surgical pathological and cytopathological findings from a patient with primary urethral clear-cell adenocarcinoma and describe next-generation sequencing results for this patient's unique tumor-the first such reported characterization of molecular aberrations in urethral clear-cell adenocarcinoma at the transcriptomic and genomic levels. Transcriptome analysis revealed novel gene fusion candidates, including ANKRD28-FNDC3B. Whole-exome analysis demonstrated focal copy number loss at the SMAD4 and ARID2 loci and 38 somatic mutations, including a truncating mutation in ATM and a novel nonsynonymous mutation in ALK.

Clear cell adenocarcinoma of the renal pelvis in a male patient

Carcinoma of the renal pelvis is an uncommon renal neoplasm. Clear cell adenocarcinoma in the urinary tract is rare and has a histomorphology resembling that of the female genital tract. We herein present a case of clear cell adenocarcinoma of the renal pelvis, which is the first example in a male patient to our knowledge. A 54-year-old man presented with right flank pain. The tumor was associated with renal stones and hydronephrosis and invaded into the peripelvic fat tissue with regional lymph node metastasis. The patient died of metastatic disease six months postoperatively. Histologically, the tumor showed complex papillary architecture lined with clear and hobnail cells. Clear cell adenocarcinoma of the renal pelvis may pose a diagnostic challenge on histological grounds, particularly in the distinction from renal cell carcinoma. The immunohistochemical stains could help confirm the diagnosis. Due to its rarity, an effective treatment regimen remains to be determined.

Laser-assisted microdissection in translational research: theory, technical considerations, and future applications

Molecular profiling already exerts a profound influence on biomedical research and disease management. Microdissection technologies contribute to the molecular profiling of diseases, enabling investigators to probe genetic characteristics and dissect functional physiology within specific cell populations. Laser-capture microdissection (LCM), in particular, permits collation of genetic, epigenetic, and gene expression differences between normal, premalignant, and malignant cell populations. Its selectivity for specific cell populations promises to greatly improve the diagnosis and management of many human diseases. LCM has been extensively used in cancer research, contributing to the understanding of tumor biology by mutation detection, clonality analysis, epigenetic alteration assessment, gene expression profiling, proteomics, and metabolomics. In this review, we focus on LCM applications for DNA, RNA, and protein analysis in specific cell types and on commercially available LCM platforms. These analyses could clinically be used as aids to cancer diagnosis, clinical management, genomic profile studies, and targeted therapy. In this review, we also discuss the technical details of tissue preparation, analytical yields, tissue selection, and selected applications using LCM.

Histology and immunohistochemistry of clear cell adenocarcinoma of the urethra: histogenesis and diagnostic problems

Clear cell adenocarcinoma (CCAC) of the urethra is a rare neoplasm, morphologically identical to its homologue arising in the female genital tract. The histogenesis of this neoplasm is uncertain. We present clinical, histopathologic, and immunohistochemical findings of four CCAC of the urethra and discuss the histogenesis and difficulties in diagnosis and differential diagnosis. CCAC of the urethra occurred in females (4/4). Two neoplasms were identified in urethral diverticulum; one of the two cases, in close proximity to a nephrogenic adenoma. CCAC exhibited tubulocystic, papillary, and diffuse/solid growth patterns. The neoplastic cells were cuboidal or columnar with eosinophilic or clear cytoplasm, and nuclear pleomorphism of at least moderate degree. Hobnail features and tumor necrosis were also observed. CCAC expressed p53 (4/4), AMACR (3/4), vimentin (3/4), PAX8 (2/4), CK7 (2/4), cytokeratin 34betaE12 (2/4), RCC (1/4), and CK20 (1/4) and were negative for PSA, WT1, ER, CA 125, uroplakin III, p16, and p63. The immunohistochemical profile supports a possible renal tubular cell differentiation/mesonephric origin for some urethral CCAC. Nephrogenic adenoma and metastatic clear cell carcinoma are the most important differential diagnostic considerations. Multicenter studies on more cases may improve our understanding of this malignancy.

A case of clear cell adenocarcinoma arising from the urethral diverticulum: Utility of urinary cytology and immunohistochemistry

Carcinomas rarely arise from the urethral diverticulum. In this report, we present a case of clear cell adenocarcinoma arising from the urethral diverticulum. A 42-year-old woman complained of bloody discharge and lower back pain. Imaging studies showed a tumor involving the region surrounding the urethra and cystourethroscopy showed papillary and villous tumors in the urethral diverticula. Cytology of the urine sediment showed papillary or spherical clusters of atypical cells, some of which had clear abundant cytoplasm and formed mirror ball-like clusters, suggesting adenocarcinoma. Although histological diagnosis was indeterminate by biopsy and transurethral resection (TUR) because of absence of stromal invasion, surgically resected specimen via cysturethrectomy revealed that the tumor was clear cell carcinoma. Urinary cytological findings and immunohistochemical analysis for CD15, Ki-67, and p53 might be useful for accurate diagnosis of clear cell adenocarcinoma that arises from the urethral diverticulum when sufficient materials are not available by biopsy and TUR.

Cytologic findings of clear cell adenocarcinoma of the urethra: a case report

Clear cell adenocarcinoma of the urethra is a rare disease entity with an uncertain histogenesis. Here, we present a case of primary clear cell adenocarcinoma of the female urethra with its cytological findings. A 54-year-old woman presented with a painless gross hematuria lasting 3 months. On vaginal sonography, there was a sausage-like, elongated mass in the urethra, measuring 3.8×4.3 cm. The voided urine cytology revealed small clusters of rounded or papillary cells. The necrotic debris and inflammatory cells were present within some clusters of tumor cells. These tumor cells were enlarged and had abundant clear or granular cytoplasm with cytoplasmic vacuoles. The nucleus was granular and contained vesicular chromatin with prominent nucleoli. The hobnail cells and hyaline globules were also present as in a histologic section. The histologic findings were compatible with clear cell adenocarcinoma. The tumor showed distinctive cytological features. Cytologically, however, it is necessary to make a differential diagnosis from other adenocarcinoma or high-grade urothelial carcinoma.

Primary clear cell adenocarcinoma of the bladder with recurrence: a case report and literature review

Clear cell carcinoma of the bladder is a rare tumor of the bladder. There are few reports available on this rare disease, and no cases with recurrence were reported. Here we present a case of 68-year-old woman with primary clear cell carcinoma of the bladder, who underwent repeat TUR-BT and tumor recurrence. We also reviewed the previous treatments and prognoses in previous case reports and evaluate the proper treatment for this disease. Once the diagnosis is determined, the radical surgery should be recommended. The recurrence is not prevented based on post-TUR intravesical therapy.

Clinical utility of immunohistochemistry in the diagnoses of urinary bladder neoplasia

Urothelial carcinomas demonstrate diverse morphologic and immunologic features that frequently lead to diagnostic challenges. Recent advances have identified a number of immunohistochemical stains that, when used in the context of a panel, can be a valuable tool in properly classifying primary urothelial carcinoma and carcinomas secondarily involving the urinary bladder. In addition, new biomarkers prove helpful in the staging of bladder carcinoma. In this article, we review the clinical utility of immunohistochemistry in a series of diagnostic scenarios, including flat urothelial lesions with atypia, rare variants of urothelial carcinoma, primary adenocarcinoma versus secondary colorectal tumors, distinguishing prostate from urothelial carcinoma, and the utility of smoothelin in staging bladder carcinoma. Emphasis is placed on panels of commonly used biomarkers to establish diagnoses.

[Vesiculectomy with laparoscopic partial prostatectomy in the treatment of primary adenocarcinoma of the seminal vesicle with carcinomatous transformation of the ejaculatory duct]

INTRODUCTION

Primary adenocarcinoma of the seminal vesicle is an extremely rare condition. Some cases have been described in relation to congenital seminal vesicle cysts, which is often also associated with agenesia or ipsilateral renal disgenesia. The rareness of this type of lesions makes it difficult to plan a regulated surgical approach for them, although they are often treated by simple exeresis or exenteration, depending on their stage at the beginning.

MATERIALS AND METHODS

We present a new surgical technique that consists of radical vesiculectomy associated with laparoscopic partial prostatectomy (total segmentary) of the central area to successfully treat primary seminal vesicle adenocarcinoma in a young man who was diagnosed through an azoospermia study.

RESULTS

A study of the scan (MRI) with diffusion and the transrectal biopsy of the mass allowed us to make a thorough preoperative evaluation of the case, confirming the malignity and precociousness of the lesion. The laparoscopic approach allowed us to perform a pelvic lymphadenectomy and transperitoneal exeresis, including the central prostate area and suture of the posterior face of the urethra at the height of the apex of the prostate. The wall of the seminal cyst lesion confirmed infiltrating clear cell adenocarcinoma and non-invasive adenocarcinoma in the prostate segment of the central gland in the light of the ejaculatory conduct with "in situ" growth. Thus, the surgical specimen allowed radical exeresis with negative margins, guaranteeing minimally invasive surgery with preservation of continence and erection.

CONCLUSION

We describe a new integral approach for the radical surgery of localized primary adenocarcinoma of the seminal vesicle. Despite its exceptional nature, the case allowed for a double reflection: a) The study of diffusion with MRI may suggest the diagnosis of malignity in this type of lesions; and b) Radical surgical treatment must include exeresis of the central portion of the prostate gland.

Bladder cancer: translating molecular genetic insights into clinical practice

Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.

Clear cell adenocarcinoma of the bladder and urethra: cases diffusely mimicking nephrogenic adenoma

Although clear cell adenocarcinoma have been described focally mimicking nephrogenic adenoma, we have identified a subset of clear cell adenocarcinoma that diffusely resembles nephrogenic adenoma (nephrogenic adenoma-like clear cell adenocarcinoma). Twelve classic clear cell adenocarcinomas of the bladder and urethra and 7 nephrogenic adenoma-like clear cell adenocarcinomas were compared to 10 nephrogenic adenomas. Classic clear cell adenocarcinomas and nephrogenic adenoma-like clear cell adenocarcinomas comprised 4 men and 15 women. The following features were seen in classic clear cell adenocarcinomas: nephrogenic adenoma-like clear cell adenocarcinomas: predominantly solid pattern (7/12:0/7), marked nuclear pleomorphism (7/12:1/7), prominent nucleoli (5/12:1/7), clear cytoplasm in 50% or greater of tumor (7/12:0/7), and necrosis (8/12:3/7), although the necrosis in nephrogenic adenoma-like clear cell adenocarcinomas was often focal and intraluminal. Both patterns of clear cell adenocarcinomas showed prominent hobnail features, although more pronounced in nephrogenic adenoma-like clear cell adenocarcinomas. Muscularis propria invasion was seen in 5 of 9 classic clear cell adenocarcinomas and 6 of 6 nephrogenic adenoma-like clear cell adenocarcinomas, where evaluable. Classic clear cell adenocarcinoma was associated with urothelial carcinoma (n = 2) and endometriosis (n = 1). The Ki-67 rate in clear cell adenocarcinomas ranged from 10% to 80% compared with 0% to 5% in nephrogenic adenoma. The following antibodies were not helpful in distinguishing nephrogenic adenoma-like clear cell adenocarcinoma from nephrogenic adenoma: CD10, estrogen receptor, p63, high-molecular-weight cytokeratin, and alpha-methylacyl coenzyme-A racemase. PAX2 expression was more frequent in nephrogenic adenoma (89%) compared to both patterns of clear cell adenocarcinoma (29%-32%). The key features discriminating between nephrogenic adenoma-like clear cell adenocarcinoma and nephrogenic adenoma include occasional clear cells, more prominent pleomorphism especially hyperchromatic enlarged nuclei, and extensive muscular invasion. Presence of mitoses and a high rate of Ki-67 expression in lesions resembling nephrogenic adenoma require clinical correlation, close follow-up, and repeat biopsy with more extensive sampling.

Histological variants of urothelial carcinoma: diagnostic, therapeutic and prognostic implications

It is well established that invasive urothelial carcinoma, involving the urinary bladder and renal pelvis, has marked propensity for divergent differentiation. In recent years, several 'variant' morphologies have been described and most have been recognized in the 2004 World Health Organization Classification. These histological variants of urothelial carcinoma have clinical significance at various levels, including diagnostic, that is, awareness of the morphological variant is essential in order to avoid diagnostic misinterpretations; prognostic for patient risk stratification; and therapeutic, where a diagnostic assignment of a particular variant may be associated with the administration of a therapy distinctive from that used in conventional invasive urothelial carcinoma. The diagnoses of micropapillary urothelial carcinoma, small-cell carcinoma, lymphoepithelioma-like carcinoma and sarcomatoid carcinoma are prime examples where treatment protocols may be different than the usual muscle-invasive bladder cancer. This review discusses the variants of urothelial carcinoma, outlining for each the diagnostic features, differential diagnostic considerations and the clinical significance.

Divergent differentiation in urothelial carcinoma and other bladder cancer subtypes with selected mimics

Conventional urothelial carcinoma accounts for most carcinomas of the urinary tract lining. However, neoplastic urothelium has the capacity to demonstrate enormous plasticity. A variety of unusual architectural patterns of urothelial carcinoma, such as the nested, microcystic and inverted variants, can be mistaken for reactive processes or benign tumours. Others such as the micropapillary, plasmacytoid and discohesive variants, can mimic metastatic tumour from other sites. The micropapillary variant in particular is more aggressive. In addition, urothelial carcinoma has a propensity to demonstrate divergent differentiation with glandular, squamous, small cell neuroendocrine, lymphoepithelioma-like, sarcomatoid or other elements. Pure squamous carcinoma or adenocarcinoma (the latter in particular) can be difficult to distinguish from contiguous or metastatic spread. Some variants have prognostic and potential therapeutic implications. Molecular genetic evidence has emerged recently supporting a close relationship between urothelial carcinoma and various divergent elements. Sarcomatoid carcinoma and its differential diagnosis with other spindle cell lesions of urinary tract will be covered in a separate review.