Urinary bladder pathology 2004: An update

Prognostic performance of the 1973 and 2004 WHO grading classification in upper tract urothelial carcinoma

BACKGROUND

Grading of upper tract urothelial carcinoma (UTUC) is routinely used in clinical practice; however, reports concerning prognostic performance of different grading systems are contradictory. We aim to assess the clinical reliability of the 1973 and 2004 World Health Organization (WHO) grading classification systems in UTUC.

PATIENTS AND METHODS

We retrospectively evaluated 458 consecutive patients with UTUC from 2008 to 2013. The postoperative tumor grades were evaluated by a single uropathologist using the 1973 and 2004 WHO grade classification systems. The Kaplan-Meier method was used to estimate cancer-specific survival (CSS) and overall survival (OS). Univariate and multivariate analyses were used to test the association between clinical variables and the CSS and OS rates.

RESULTS

There were 133 (29.0%) low-grade patients and 325 (71.0%) high-grade patients. The 3-year CSS rates were 87.0% and 76.0% for G2 and G3 disease and 89.0% and 80.0% for low- and high-grade disease according to the 2004 system, respectively. For all UTUC patients, there were significant differences in the CSS and OS rates between G2 and G3 cases, as well as between the low- and high-grade groups. The CSS and OS rates were significantly different between the G2 and G3 cases for the overall high-grade population (CSS: P = 0.003; OS: P = 0.009), while no significant difference emerged between low- and high-grade tumors in G2 UTUC patients (CSS: P = 0.717; OS: P = 0.280). In the subgroup of high-grade non-muscle-invasive tumors, the 1973 WHO grading system was an independent predictor of CSS (P = 0.045).

CONCLUSIONS

The results support the hypothesis that the 1973 WHO system is superior to the 2004 system for predicting clinical outcomes in patients with non-muscle-invasive UTUC.

Diffusion-weighted magnetic resonance imaging in cystic renal masses

INTRODUCTION

We aimed to introduce the diagnostic value of diffusion-weighted (DWI) magnetic resonance imaging (MRI) for distinguishing benign and malignant renal cystic masses.

METHODS

Abdominal DWI-MRIs of patients with Bosniak categories 2F, 3, and 4 cystic renal masses were evaluated retrospectively. Cystic masses were assigned as benign or malignant according to histopathological or followup MRI findings and compared with apparent diffusion coefficient (ADC) values.

RESULTS

There were 30 patients (18 males and 12 females, mean age was 59.23 ± 12.08 years [range 38-83 years]) with cystic renal masses (eight Bosniak category 2F, 12 Bosniak category 3, 10 Bosniak category 4). Among them, 14 cysts were diagnosed as benign and 16 as malignant by followup imaging or histopathological findings. For the malignant lesions, the mean ADC values were lower than for benign lesions (p=0.001). An ADC value of ≤2.28 ×10^-6 mm²/s or less had a sensitivity of 75% and a specificity of 92.86% for detecting malignancy.

CONCLUSIONS

ADC can improve the diagnostic performance of MRI in the evaluation of complex renal cysts when used together with conventional MRI sequences.

Immunohistochemistry and Fluorescence In Situ Hybridization Can Inform the Differential Diagnosis of Low-Grade Noninvasive Urothelial Carcinoma with an Inverted Growth Pattern and Inverted Urothelial Papilloma

Urothelial carcinoma (UC) comprises a heterogeneous group of epithelial neoplasms with diverse biological behaviors and variable clinical outcomes. Distinguishing UC histological subtypes has become increasingly important because prognoses and therapy can dramatically differ among subtypes. In clinical work, overlapping morphological findings between low-grade noninvasive UC (LGNUC), which exhibits an inverted growth pattern, and inverted urothelial papilloma (IUP) can make subclassification difficult. We propose a combination of immunohistochemistry (IHC) and molecular cytogenetics for subtyping these clinical entities. In our study, tissue microarray immunohistochemical profiles of Ki-67, p53, cytokeratin 20 (CK20) and cyclinD1 were assessed. Molecular genetic alterations such as the gain of chromosomes 3, 7 or 17 or the homozygous loss of 9p21 were also assessed for their usefulness in differentiating these conditions. Based on our analysis, Ki-67 and CK20 may be useful for the differential diagnosis of these two tumor types. Fluorescence in situ hybridization (FISH) can also provide important data in cases in which the malignant nature of an inverted urothelial neoplasm is unclear. LGNUC with an inverted growth pattern that is negative for both Ki-67 and CK20 can be positively detected using FISH.

Bladder preservation with brachytherapy compared to cystectomy for T1-T3 muscle-invasive bladder cancer: a systematic review

Purpose

Radical cystectomy currently is the treatment of choice in muscle-invasive bladder cancer. However, cystectomy is associated with considerable morbidity. Bladder sparing treatment consists of transurethral resection of the tumor (with or without partial cystectomy), external beam radiotherapy, and brachytherapy. The purpose of this study is to compare bladder preservation with brachytherapy to cystectomy by a systematic review.

Material and methods

A systematic review was conducted using PubMed electronic database. Article selection was done independently by two authors. Data were extracted on cause-specific survival and overall survival at 2, 5, and 10 years. Comparison of the two treatment modalities was done by a Weibull survival analysis with metaregression analysis and estimation of Hazard Ratio's (HR's) with 95% confidence intervals (CI).

Results

Large differences in tumor staging and tumor grading were found between cystectomy and bladder sparing series. The adjusted HR's for cause-specific survival and overall survival were 1.27 (95% CI: 1.15-1.40) and 0.85 (95% CI: 0.84-0.87), respectively for bladder sparing relative to radical cystectomy.

Conclusions

Robustness of the analysis is hampered by the retrospective character of the study and differences in patient characteristics. For selected cases, bladder sparing by brachytherapy leads to at least similar overall survival compared to radical cystectomy for muscle invasive bladder cancer.

A contemporary update on pathology reporting for urinary bladder cancer

Providing the best management for patients with bladder cancer relies on close cooperation among uro-oncologists and pathologists. The pathologist is involved in the diagnosis and assessment of prognostic and therapeutic factors in bladder biopsies, transurethral resection (TUR) and cystectomy specimens. The pathologist must report accurately the key features using terms that are well understood by clinicians. Adequate clinical information is important to pathologists in deciding the best approach in handling and processing the surgical specimens.

When urothelial differentiation pathways go wrong: implications for bladder cancer development and progression

Differentiation is defined as the ability of a cell to acquire full functional behavior. For instance, the function of bladder urothelium is to act as a barrier to the diffusion of solutes into or out of the urine after excretion by the kidney. The urothelium also serves to protect the detrusor muscle from toxins present in stored urine. A major event in the initiation and progression of bladder cancer is loss of urothelial differentiation. This is important because less differentiated urothelial tumors (higher histologic tumor grade) are typically associated with increased biologic and clinical aggressiveness. The differentiation status of urothelial carcinomas can be assessed by histopathologic examination and is reflected in the assignment of a histologic grade (low-grade or high-grade). Although typically limited to morphologic evaluation in most routine diagnostic practices, tumor grade can also be assessed using biochemical markers. Indeed, current pathological analysis of tumor specimens is increasingly reliant on molecular phenotyping. Thus, high priorities for bladder cancer research include identification of (1) biomarkers that will enable the identification of high grade T1 tumors that pose the most threat and require the most aggressive treatment; (2) biomarkers that predict the likelihood that a low grade, American Joint Committee on Cancer stage pTa bladder tumor will progress into an invasive carcinoma with metastatic potential; (3) biomarkers that indicate which pTa tumors are most likely to recur, thus enabling clinicians to prospectively identify patients who require aggressive treatment; and (4) how these markers might contribute to biological processes that underlie tumor progression and metastasis, potentially through loss of terminal differentiation. This review will discuss the proteins associated with urothelial cell differentiation, with a focus on those implicated in bladder cancer, and other proteins that may be involved in neoplastic progression. It is hoped that ongoing discoveries associated with the study of these differentiation-promoting proteins can be translated into the clinic to positively impact patient care.

Differential expression of immunohistochemical markers in bladder smooth muscle and myofibroblasts, and the potential utility of desmin, smoothelin, and vimentin in staging of bladder carcinoma

Distinguishing bladder muscularis propria from muscularis mucosae can be problematic especially in transurethral resection specimens performed for bladder carcinoma. Moreover, bladder carcinoma can be associated with a proliferative/desmoplastic myofibroblastic response that can resemble smooth muscle and potentially lead to overdiagnosis of muscularis propria invasion. The aim of this study was to investigate the potential role of immunohistochemistry in staging bladder carcinoma by evaluating the expression of different markers in myofibroblasts and nonvascular smooth muscle cells in 15 cases of invasive bladder carcinoma. Reactive myofibroblasts were consistently positive for vimentin and smooth muscle actin, consistently negative for caldesmon, desmin, and smoothelin, and had variable expression of actin and CD10. Nonvascular smooth muscle cells of the bladder were consistently positive for smooth muscle actin, actin, desmin, and caldesmon, and consistently negative for CD10. In contrast to smooth muscle cells of the muscularis propria, which displayed strong smoothelin expression in all 15 cases, the smooth muscle cells of the muscularis mucosae displayed moderate smoothelin expression in only 1 (9%) of 11 cases (P=10(-7)). Surprisingly, although strongly highlighting endothelial and endomysial cells, the smooth muscle cells of the muscularis propria weakly expressed vimentin in only 1 (7%) of 15 cases, whereas smooth muscle cells of the muscularis mucosae had moderate or strong expression in 9 (82%) of 11 cases (P=0.00016). The sensitivity and specificity of desmin or caldesmon expression for smooth muscle cells were 100%. The sensitivity and specificity of strong smoothelin expression for muscularis propria were 100%, whereas those of absent vimentin expression were 93 and 82%, respectively. Although morphology remains the gold standard, the findings suggest that immunohistochemistry, using a panel composed of desmin, smoothelin, and vimentin, may be potentially useful for staging of bladder carcinoma. Confirmatory larger-scale studies, especially on transurethral resection specimens, are warranted.

Adenocarcinoma of the urinary bladder presenting as locally advanced endometrial carcinoma. Case report and review of the literature

BACKGROUND

Carcinoma of the urinary bladder that occurs after urinary diversion is a rare entity. We report a case of an adenocarcinoma arising in a defunctionalized bladder that presented as locally advanced endometrial carcinoma.

CASE

A 77-year-old presented with postmenopausal bleeding and mucous vaginal discharge. She had a prior history of urinary diversion via a Koch pouch. Examination revealed a mass protruding through the cervix and possibly involving the bladder anteriorly. The patient underwent anterior pelvic exenteration for a locally advanced mucinous carcinoma thought to be arising from the uterus and invading into the bladder. Final pathology, however, was consistent with a primary bladder carcinoma.

CONCLUSION

Carcinoma developing in the bladder after urinary diversion presents at an advanced stage and has associated poor overall survival.

Harnblasentumoren

Increasing knowledge in molecular genetic research on urinary bladder carcinoma has allowed us to classify the morphological picture on the basis of a better understanding. But this new knowledge will only be ground-breaking if it can be correlated with the clinical outcome of urinary bladder tumours and with histopathological findings. The use of the new 2004 WHO classification results in a standardized diagnosis of urothelial tumours by means of an exact definition of the subgroups. In the future, trials can thus be compared worldwide and risk profiles can be stratified. Further research in molecular genetics and correlation with the current classification together with molecular biological techniques may allow refinement of this scheme, e.g. by immunohistochemical subclassifications, enabling identification of potentially genetically unstable tumours. In this paper we present the new 2004 WHO classification of urinary bladder tumours emphasizing the changes in relation to the former classifications focusing on histological typing, grading and molecular characterization. Until the new classification is finally validated, and those working in the field have become familiar with it, the WHO classification of 1973 should be mentioned additionally in the histopathological report.