Microcystic variant of urothelial carcinoma

[Morphological variants of the invasive urothelial cell carcinoma.]

Urothelial cell carcinoma is the most common malignant tumor of the urinary tract, which develops in the renal pelvis, ureter, and bladder, and rarely it develops in the ureter. Histologically, urothelial cell carcinoma is categorized into non-invasive and invasive forms. Non-invasive urothelial cell carcinoma has papillary growth, it is usually well differentiated, and has a favorable outcome, while invasive urothelial cell carcinoma infiltratively spreads the organs of origin, it is typically poorly differentiated, and often associated with a poor prognosis. In the case of invasive urothelial cell carcinoma, the clinical course is primarily determined by the depth of invasion, but according to recent data, morphological variants of urothelial cell carcinoma respond differently to oncological treatments, and their biological behavior is also distinct. These subtypes and variants are significantly underdiagnosed in Hungary and internationally because the criteria for histological diagnosis are not clear for many subsets. The latest 2022 WHO classification of urinary tract tumors significantly clarified the definitions of various subtypes and variants. In this paper, utilizing the current classification, we review and explain these subtypes' morphological, immunohistochemical, differential diagnostic, prognostic, and predictive characteristics intending to make them appear as much as possible in everyday diagnostic practice. Also, the work aims to present the individual urothelial cell carcinoma subtypes and variants to the Hungarian community of pathologists, oncologists, and urologists, so that the previously high level of urological oncology care can become even more personalized. Orv Hetil. 2023; 164(40): 1567-1582.

Nephrogenic Adenoma Arising From a Female Urethral Diverticulum: A Case Report and Potential Diagnostic Pitfalls

Nephrogenic adenoma is a benign lesion of the urothelial tract characterized by tubules surrounded by thick, hyalinized basement membranes. There is a great variety of architectural patterns within nephrogenic adenomas, including patterns that mimic malignancy, such as focal clear or hobnail cells, areas of significant nuclear atypia, mitosis, and isolated cystic changes. This represents a diagnostic pitfall, where a malignant lesion can be mistaken for a nephrogenic adenoma, leading to a delay in diagnosis and treatment that adversely affects the outcome. In this case report, we describe a nephrogenic adenoma arising in a female urethral diverticulum and discuss the differential diagnosis, which includes clear cell carcinomas, microcystic variant urothelial carcinomas, and Skene's gland cysts.

The optimal management of variant histology in muscle invasive bladder cancer

Bladder cancer is a heterogenous disease that is associated with tangible mortality in muscle invasive disease. The WHO 2016 classification of urothelial tumours reflects the contemporary approach towards histological variants in bladder cancer, including variants of urothelial carcinoma (UC) and non-urothelial variants. This review focuses on variant histology in UC, and discusses the importance of accurate histological diagnosis, and subsequent risk stratification and therapeutic decision making based on proper variant recognition. Most urothelial variants are associated with poorer outcomes compared to conventional UC, although some perform reasonably better. However, high quality evidence detailing optimal treatment and survival outcomes are still lacking in literature, due to the rarity of these cases.

Microcystic urothelial carcinoma: a case report

Microcystic urothelial carcinoma (MUC) is a rare variant of urothelial carcinoma that is highly aggressive with poor prognosis. Due to the scarcity of cases, its histologic morphology and immunohistochemical characteristics are still not clear. This paper reports a 71-year old female patient with gross hematuria and abdominal pain. Imaging examination showed that the bladder wall was thickened, and rough. A soft tissue mass was seen in the bladder and the left lower ureter, and the boundary between the bladder and the uterus and bilateral adnexa was not clear. Multiple enlarged lymph nodes were seen around the abdominal aorta and left iliac artery. Cystoscopy showed diffuse thickening and edema of the left wall of the bladder, local rough bleeding, and histopathologic results showed that the lesions were consistent with high-grade invasive urothelial carcinoma. Radical cystectomy and bilateral ovariectomy were performed. By microscopic observation the tumor showed infiltrative growth with cystic structures of different sizes. Mitotic figures were frequent and a large amount of mucus was in the stroma. The same type of cancer was found in the left ovary. Immunohistochemistry showed CK5/6 +, p63 +, Pax-8, MUC5AC, CK7, and Ki67 was 50%. Postoperative pathology confirmed that MUC involved the left ureter with ovarian metastasis. Two months after the operation, the patient died of vascular invasion. Because tumor cells were bland in morphology and had no specific immunohistochemical markers, they were easily missed and misdiagnosed by pathologists. Here, we describe this case and analyze it with relevant literature to deepen understanding of MUC.

Microcystic urothelial carcinoma of the bladder: A case report

Microcystic variant of urothelial carcinoma was recently added to the World Health organization classification of transitional cell carcinoma. This variant is characterized by its aggressiveness explaining the low long-term survival rate of the patients. Larger studies are needed to determine the adequate treatment course. We present the case of a 71-year-old patient who was diagnosed with muscle invasive microcystic variant of urothelial carcinoma of the bladder and remained free of tumor recurrence two year after surgery.

Effects of Variant Histology on the Oncologic Outcomes of Patients With Upper Urinary Tract Carcinoma After Radical Nephroureterectomy: A Propensity Score-Matched Analysis

PURPOSE

To determine the prognostic effect of upper tract urothelial carcinoma (UTUC) with variant histology (VH) after radical nephroureterectomy (RNU).

PATIENTS AND METHODS

The data of 1173 patients who received RNU for UTUC without neoadjuvant chemotherapy in 11 institutions between 2002 and 2016 were retrospectively reviewed. A matched propensity score analysis was performed. Clinicopathologic variables, recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were compared between patients with pure UTUC and patients with UTUC and VH. Univariate and multivariate Cox proportional regression models were used to determine the independent variables associated with oncologic outcomes.

RESULTS

UTUC with VH was observed in 93 patients (7.9%). After propensity score matching, UTUC with VH showed no difference in clinicopathologic features compared to pure UTUC; however, it was associated with shorter RFS, CSS, and OS (log rank, P = .011, P = .002, P = .006, respectively). Additionally, the multivariate analysis revealed that VH was independently associated with a poor RFS [hazard ratio (HR) = 1.92; 95% confidence interval (CI), 1.27-2.89; P = .002], CSS (HR = 4.47; 95% CI, 1.99-10.1; P = .001), and OS (HR = 3.00; 95% CI, 1.55-5.78; P = .001). However, the Kaplan-Meier method revealed that differences in RFS, CSS, and OS were not significant in patients who received adjuvant chemotherapy (log rank, P = .562, P = .060, P = .153, respectively).

CONCLUSION

UTUC with VH was independently associated with poor oncologic outcomes in patients with UTUC after RNU. Although patients with UTUC and VH had a poor prognosis compared to patients with pure UTUC, adjuvant chemotherapy would be helpful in improving the survival rates of these patients.

Podocalyxin-like and RNA-binding motif protein 3 are prognostic biomarkers in urothelial bladder cancer: a validatory study

BACKGROUND

Urothelial bladder cancer (UBC) is a disease that often is discovered when the tumour is non-muscle invasive, i.e. in Ta or T1 stage. Some patients will progress into muscle-invasive disease, a potentially deadly condition. Although there are some prognostic models, the need for prognostic and predictive biomarkers is considerate and urgent. Membranous expression of podocalyxin-like protein 1 (PODXL) and low expression of the RNA-binding motif 3 (RBM3) has previously been shown to be associated with an aggressive tumour phenotype and poor prognosis in several forms of cancer, including UBC. In this study, we sought to validate the prognostic impact of PODXL and RBM3 in an independent cohort of UBC.

METHODS

Using tissue microarrays and immunohistochemistry, PODXL and RBM3 expression was evaluated in 272 incident UBC cases from the prospective, population-based cohort study Malmö Diet and Cancer. Kaplan-Meier analysis and Cox proportional hazards modelling were used to evaluate the prognostic impact of these markers on 5-year overall survival (OS).

RESULTS

In line with previous studies, both membranous PODXL expression and low RBM3 expression was significantly associated with disadvantageous clinicopathological features. Membranous PODXL expression was significantly associated with a reduced 5-year overall survival in the entire cohort (univariable HR 3.28; 95% CI 1.89-5.69), but this association did not remain significant in multivariable analysis. In T1 tumours, PODXL was significantly associated with reduced survival in univariable analysis (HR = 2.83; 95% CI 1.04-7.72) and borderline significant in multivariable analysis (HR = 2.60; 95% CI 0.91-7.39). Low RBM3 expression was an independent predictor of a reduced survival in the entire cohort (univariable HR 3.19; 95% CI 2.02-5.04, and multivariable HR 1.85; 95% CI 1.11-3.09), and in T1 tumours (univariable HR 2.64; 95% CI 1.11-6.27, and multivariable HR 2.63; 95% CI 1.01-6.84).

CONCLUSIONS

A link between membranous PODXL expression and clinically more aggressive tumours was further confirmed, but PODXL expression was not an independent prognostic biomarker in this study. Low RBM3 expression was validated as an independent factor of poor prognosis in UBC, including T1 disease. These findings suggest that these biomarkers could be useful in stratifying patients with non-muscle invasive disease for more aggressive first line treatment.