Primary clear-cell urothelial carcinoma of urinary bladder: a not-so-clear entity with review of literature

Primary clear-cell urothelial carcinoma (CCUC) is an uncommon type of urothelial cancer with only 16 cases reported in published literature. Due to the rarity of the tumour, its clinical and prognostic values have not been clearly understood. We present one such rare clinical diagnosis in a 60-year- old man who underwent radical cystectomy (RC) with ileal conduit for urinary bladder cancer. Histopathology showed features of high-grade CCUC infiltrating the muscularis propria. Immunohistochemistry revealed diffuse immunopositivity of pan cytokeratin (CK), GATA3, P40, CK7 but was immunonegative for CD10 and vimentin. Our patient expired 4 months after diagnosis. CCUC has recently been included in the WHO 2016 classification of urothelial tumours. Most of the patients present with poor prognosis. Accurate diagnosis and recognition of this unusual variant are essential for better patient management and prognosis. Early RC seems to be the preferred way of management.

Inverted urothelial papilloma: A review of diagnostic pitfalls and clinical management

Inverted urothelial papilloma (IUP) is a rare, non-invasive endophytic lesion that accounts for 1‒2% of urothelial tumours. On cystoscopy, IUP appears as a pedunculated/papillary mass with a smooth surface. On microscopy, IUP has an endophytic growth pattern with the bulk of the tumour covered by a superficial layer of urothelium, which can be hyperplastic or attenuated. The cytology should be bland, with uniform, spindled cells arranged in anastomosing trabeculae and cords with peripheral palisading of basaloid cells. Exophytic papillae and mitotic activity should be absent or focal. Pseudoglandular spaces and squamous metaplasia may also be present. There are distinct molecular differences between IUP and urothelial carcinoma (UC). IUP rarely has mutations of FGFR3, homozygous loss of 9p21, or gain of chromosomes 3, 7, and 17, whereas these mutations are frequently seen in UC. In addition, IUP is much less likely to have TERT mutations compared to UC. Immunohistochemistry can also be helpful in distinguishing the two entities as IUP is typically negative for CK20 and has a low Ki-67 proliferation index. Positivity for p53 may be seen in a minority of IUP. IUP can recur and be seen in association with UC. Distinguishing IUP from UC can be difficult due to the similarity between the two entities both on cystoscopy and histology, as up to 25% of UCs will also have inverted growth. Given the morphologic variants of IUP and UC, it is possible for a diagnostic error to occur, which can significantly impact patient management.

Revealing a Pre-neoplastic Renal Tubular Lesion by p-S6 Protein Immunohistochemistry after Rat Exposure to Aristolochic Acid

Aristolochic acid (AA) has, in the last decade, become widely promoted as the cause of the Balkan endemic nephropathy and associated renal or urothelial tumours, although without substantial focal evidence of the quantitative dietary exposure via bread in specific households in hyperendemic villages. Occasional ethnobotanical use of Aristolochia clematitis might be a source of AA, and Pliocene lignite contamination of well-water is also a putative health risk factor. The aim of this study was two-fold: to verify if extracts of A. clematitis and Pliocene, or AA by itself, could induce the development of renal or urothelial tumours, and to test the utility of the ribosomal protein p-S6 to identify preneoplastic transformation. Rats were given extracts of A. clematitis in drinking water or AA I, by gavage. After seven months, renal morphology was studied using conventional haematoxylin and eosin and immunohistochemistry for ribosomal p-S6 protein. Plant extracts (cumulative AA approximately 1.8 g/kg b.w.) were tolerated and caused no gross pathology or renal histopathological change, with only faint diffuse p-S6 protein (except in the papilla) as in controls. Cumulative AA I (150 mg/kg b.w. given over 3 days) was also tolerated for seven months by all recipients, without gross pathology or kidney tumours. However, p-S6 protein over-expression was consistent particularly within the renal papilla. In one case given AA I, intense p-S6 protein staining of a proximal tubule fragment crucially matched the pre-neoplastic histology in an adjacent kidney section. We briefly discuss these findings, which compound uncertainty concerning the cause of the renal or upper urinary tract tumours of the Balkan endemic nephropathy.

Circulating tumour cells in patients with urothelial tumours: Enrichment and in vitro culture

Introduction: Results of clinical trials have demonstrated that circulating tumour cells (CTCs) are frequently detected in patients with urothelial tumours. The monitoring of CTCs has the potential to improve therapeutic management at an early stage and also to identify patients with increased risk of tumour progression or recurrence before the onset of clinically detected metastasis. In this study, we report a new effectively simplified methodology for a separation and in vitro culturing of viable CTCs from peripheral blood.Method: We include patients diagnosed with 3 types of urothelial tumours (prostate cancer, urinary bladder cancer, and kidney cancer). A size-based separation method for viable CTC - enrichment from unclothed peripheral blood has been introduced (MetaCell, Ostrava, Czech Republic). The enriched CTCs fraction was cultured directly on the separation membrane, or transferred from the membrane and cultured on any plastic surface or a microscopic slide.Results: We report a successful application of a CTCs isolation procedure in patients with urothelial cancers. The CTCs captured on the membrane are enriched with a remarkable proliferation potential. This has enabled us to set up in vitro cell cultures from the viable CTCs unaffected by any fixation buffers, antibodies or lysing solutions. Next, the CTCs were cultured in vitro for a minimum of 10 to 14 days to enable further downstream analysis (e.g., immunohistochemistry).Conclusion: We demonstrated an efficient CTCs capture platform, based on a cell size separation principle. Furthermore, we report an ability to culture the enriched cells – a critical requirement for post-isolation cellular analysis.