Micropapillary bladder cancer: a review of Léon Bérard Cancer Center experience

Current Advances in the Management of Nonurothelial Subtypes of Bladder Cancer

Urothelial cancer (UC) is the most common histology seen in bladder tumors. The 2022 WHO classification of urinary tract tumors includes a list of less common subtypes (formerly known as variants) for invasive UC which are considered high-grade tumors. This review summarizes the most recent advances in the management of selected nonurothelial subtypes of bladder cancer: squamous cell carcinoma, small cell carcinoma, sarcomatoid urothelial carcinoma, micropapillary carcinoma, plasmacytoid carcinoma, adenocarcinoma, and urachal carcinoma. The role of neoadjuvant and adjuvant chemotherapy has not been well characterized for most of these histologies, and prospective data are extremely limited. Participation in clinical trials is recommended in advanced disease.

Oncologic outcomes of neoadjuvant chemotherapy in patients with micropapillary variant urothelial carcinoma of the bladder

BACKGROUND

There is lack of consensus about the effectiveness of neoadjuvant platinum-based chemotherapy in patients with micropapillary variant urothelial carcinoma (MVUC) prior to radical cystectomy. We studied the association between neoadjuvant chemotherapy (NAC) and pathologic response (PR) among patients with micropapillary versus non-variant bladder urothelial carcinoma (UC).

METHODS

We queried the National Cancer Database to identify patients with localized UC and MVUC from 2004 to 2017. We restricted our analysis to patients who underwent radical cystectomy with or without NAC. We compared clinical, demographic, and pathologic characteristics associated with NAC. We used multivariable logistic regression and propensity score matching to examine the association between NAC and the occurrence of a pathologic complete response (pT0) and pathologic lymph node positivity (pN+). Kaplan Meier analyses and Cox proportional hazards models were used to assess overall survival (OS). We performed analyses among subsets of patients with clinical stage II (cT2) disease, as well as the entire cohort (cT2-T4).

RESULTS

We identified 18,761 patients, including 18,027 with non-variant UC and 734 patients with MVUC. Multivariable analysis revealed that NAC use was associated with greater odds of pT0 (9.64[7.62-12.82], P<0.001), and the association did not differ significantly between MVUC and non-variant UC. In a propensity matched analysis of patients with MVUC, NAC use was associated with higher odds of pT0 (OR 4.93 [2.43-13.18] P<0.001), lower odds of pN+ (OR 0.52 [0.26-0.92] P=0.047) and pathologic upstaging (OR 0.63 [0.34-0.97] P=0.042) in all stages. Similar findings were observed with cT2 disease. No significant association was seen between NAC and OS with MVUC (HR 0.89 [0.46-1.10] P=0.63), including the subset of patients with cT2 (HR 0.83 [0.49-1.06] P=0.58).

CONCLUSIONS

NAC is associated with similar pathologic and nodal responses in patients with localized MVUC and non-variant UC. Improvements in pathologic findings did not translate into OS in this retrospective hospital-based registry study.

Stromal Lymphoid Response Status in Micropapillary Urothelial Carcinomas Diagnosed in Bladder Transurethral Resections and its Comparison with Conventional Urothelial Carcinomas

OBJECTIVE

Micropapillary urothelial carcinoma is an aggressive variant of urothelial carcinoma. Evidence suggests that the relationship between the tumor and inflammatory cells is important in tumor progression and the treatment response. We evaluated the stromal lymphoid response in micropapillary urothelial carcinomas and compared it with conventional urothelial carcinomas.

MATERIAL AND METHOD

Among bladder transurethral resection materials diagnosed as 'invasive urothelial carcinoma' between January 2010-March 2017, cases with at least 5% micropapillary urothelial carcinoma were evaluated for age, gender, grade, stage, micropapillary urothelial carcinoma percentage, presence/percentage of accompanying conventional urothelial carcinoma/urothelial carcinoma variants, in situ urothelial carcinoma/micropapillary urothelial carcinoma, lymphovascular invasion, necrosis, and stromal lymphoid response. Stromal lymphoid response was scored as 0-1-2-3. All parameters were evaluated in 50 pure conventional urothelial carcinomas.

RESULTS

Among 47 micropapillary urothelial carcinomas, 41 were male. The mean age was 69 years. pT1/pT2 was 23/24. Six cases were pure MPUC. Lymphovascular invasion was present in 8, necrosis in 9 cases. Stromal lymphoid response was present and scored as 1-2-3 in 32 micropapillary urothelial carcinomas (68.1%) and 48 conventional urothelial carcinomas (96%). Micropapillary urothelial carcinomas had significantly higher lymphovascular invasion and pT2 rates and lower stromal lymphoid response.

CONCLUSION

Low stromal lymphoid response in micropapillary urothelial carcinomas can be responsible for the poor clinical outcome and impaired response to treatment of these tumors. This is the first study in the English literature to demonstrate a lower stromal lymphoid response rate in micropapillary urothelial carcinomas compared to conventional urothelial carcinomas.

Prognostic and therapeutic role of HER2 expression in micropapillary carcinoma of the bladder

Micropapillary carcinoma of the bladder (MPBC) is a variant type of infiltrating urothelial carcinoma, which portends a poor biological behavior in terms of disease stage at first diagnosis and clinical outcome; its peculiar morphology raises issues concerning the ability of tumor detection by imaging techniques and proper biopsy procedure, and the appropriate treatment for non-muscle infiltrating and muscle-infiltrating MPBC remains a matter of debate. On the basis of its established prognostic and therapeutic role in breast and gastro-esophageal cancer in the first instance, the human epidermal growth factor receptor-2 (HER2) has been investigated in selected case series of MPBC over the last 10 years. The aim of the present review was to summarize the existing evidence on HER2 status in MPBC, and to discuss its present and future utility in risk assessment and treatment choice of this uncommon, yet aggressive, disease.

Clinical risk stratification in patients with surgically resectable micropapillary bladder cancer

OBJECTIVE

To analyse survival in patients with clinically localised, surgically resectable micropapillary bladder cancer (MPBC) undergoing radical cystectomy (RC) with and without neoadjuvant chemotherapy (NAC) and develop risk strata based on outcome data.

PATIENTS AND METHODS

A review of our database identified 103 patients with surgically resectable (≤cT4acN0 cM0) MPBC who underwent RC. Survival estimates were calculated using Kaplan-Meier method and compared using log-rank tests. Classification and regression tree (CART) analysis was performed to identify risk groups for survival.

RESULTS

For the entire cohort, estimated 5-year overall survival and disease-specific survival (DSS) rates were 52% and 58%, respectively. CART analysis identified three risk subgroups: low-risk: cT1, no hydronephrosis; high-risk: ≥cT2, no hydronephrosis; and highest-risk: cTany with tumour-associated hydronephrosis. The 5-year DSS for the low-, high-, and highest-risk groups were 92%, 51%, and 17%, respectively (P < 0.001). Patients down-staged at RC <pT1 regardless of the use of NAC had the best survival (5-year DSS of 96% vs 45% for those not down-staged; P < 0.001), while those who were not down-staged despite NAC had 5-year DSS of only 17%.

CONCLUSION

In patients with surgically resectable MPBC, NAC appears to confer benefit to patients with muscle-invasive disease without hydronephrosis, while patients with cT1 disease can proceed to upfront RC. Patients with hydronephrosis do not appear to respond well to NAC and have poor prognosis regardless of treatment paradigm. However, further external validation studies are needed to support the proposed risk stratification before treatment recommendations can be made.

Micropapillary Bladder Cancer: Insights from the National Cancer Database

Introduction: Micropapillary bladder cancer (MPBC) is a variant histology of urothelial carcinoma (UC) that is associated with poor outcomes however given its rarity, little is known outside of institutional reports. We sought to use a population-level cancer database to assess survival outcomes in patients treated with surgery, radiation therapy and/or chemotherapy.

Materials and Methods: The National Cancer Database (NCDB) was queried for all cases of MPBC and UC using International Classification of Disease-O-3 morphologic codes between 2004–2014. Primary outcome was survival outcomes stratified by treatment modality. Treatments included radical cystectomy (RC) with or without neoadjuvant chemotherapy (NAC) or adjuvant chemotherapy (AC).

Results: Overall 869 patients with MPBC and 389,603 patients with UC met the inclusion criteria. Median age of the MPBC cohort was 69.9 years (58.9–80.9) with the majority of the cohort presenting with high-grade (89.3%) and muscle invasive or locally advanced disease (47.6%). For cT1 MPBC, outcomes of RC and BPS were not statistically different. For≥cT2 disease, NAC showed a survival benefit compared with RC alone for UC but not for MPBC. On multivariable analysis, MPBC histology independently predicted worse increased risk of death. On subanalysis of the MPBC RC patients, NAC did not improve survival outcomes compared with RC alone.

Conclusions: Neoadjuvant chemotherapy utilization and early cystectomy did not show a survival benefit in patients with MPBC. This histology independently predicts decreased survival and prognosis is poor regardless of treatment modality. Further research should focus on developing better treatment options for this rare disease.

The Natural History, Treatment Pattern, and Outcomes of Patients With Micropapillary Bladder Carcinoma

OBJECTIVE

Micropapillary bladder carcinoma (MPBC) is a rare variant of urothelial cancer. Most literature on MPBC is from case series reports. This study's objective was to examine the epidemiology, natural history, and prognostic factors of MPBC using a population-based registry, in addition to a literature review.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database identified 98 histologically confirmed MPBC patients from 2001 and 2007. In addition, 213 MPBC cases were identified in published literature. The clinical, demographic characteristics, treatment, and survival outcomes were compared between these 2 cohorts.

RESULTS

Among patients identified in SEER, MPBC accounted for approximately 0.01% of primary bladder tumors, with the median age of 72 years (range, 26 to 95 y). Among the MPBC cases, 56.1% had muscle invasive disease, 75.5% had poor or undifferentiated histology, and 30.6% underwent a radical or partial cystectomy. The 1-, 3-, and 5-year overall survival rates for the SEER cohort were estimated at 84.5%, 57.3%, and 42.3%, respectively. Using multivariate analysis, tumor stage and marital status were the most significant predictors for cancer-specific survival. When comparing published single-institution studies to the SEER cohort, significant differences existed in demographic characteristics including age at diagnosis, male-to-female ratio, tumor stage, cystectomy treatment, and survival outcomes, likely reflecting differences in practice patterns.

CONCLUSIONS

This is the first population-based study to analyze MPBC's epidemiology, tumor characteristics, and survival rates. Emphases on early detection, cystectomy, and multimodality in treatment are needed.

Low Grade Micropapillary Urothelial Carcinoma, Does It Exist? - Analysis of Management and Outcomes from the Surveillance, Epidemiology and End Results (SEER) Database

Objective: To elucidate the oncologic behavior of Micropapillary Urothelial Bladder Carcinoma (MPBC), a rare aggressive variant histology.

Methods: All MPBC patients in SEER 17 database were compared with those with traditional urothelial carcinoma (UC). Kaplan-Meier curves were used to determine OS and CSS. A Cox proportional hazards model (CPH) was constructed to test the effect of covariates on outcomes.

Results: From 2001-2008, 120 MPBC patients were identified, 0.1% of all bladder cancer. MPBC presented with more high grade (86.1% vs. 38.7%, p<0.0001) and more high stage disease (40.8% NMI vs. 90.4% NMI, p < 0.0001) than UC. Low grade (LG) NMI MPBC had worse OS and CSS compared to LG UC (p=0.0037, p<0.0001 respectively), and did no better than high grade (HG) NMI MPBC. No difference was detected between HG NMI MPBC and HG NMI UC pts. A CPH model controlling for stage, grade, treatment, age, race, and sex detected no significant survival difference in MPBC vs. UC (HR 1.04, p=0.7966). For NMI MPBC (n=49), only 4 patients underwent definitive therapy, of whom none died of disease. However, in those not receiving definitive therapy (n=45), 7 cancer specific deaths occurred (15.6%).

Conclusion: Controlling for stage and grade, no survival difference could be detected between MPBC and UC. Low grade NMI MPBC behaved similarly to both high grade MPBC and high grade UC. We propose that all MPBC (regardless of grade) be managed as high grade disease, and that strong consideration for definitive therapy should be given in all cases.

Primary adenocarcinoma of the urinary bladder: differential diagnosis and clinical relevance

CONTEXT

Glandular lesions of the urinary bladder include a broad spectrum of entities ranging from completely benign glandular lesions to primary and secondary malignancies. Common benign bladder lesions that exhibit glandular differentiation include cystitis cystica, cystitis glandularis, von Brunn nests, nephrogenic adenoma, intestinal metaplasia, urachal remnant, endometriosis, and prostatic-type polyp. The World Health Organization defines primary adenocarcinoma of the bladder as an epithelial malignancy with pure glandular differentiation without evidence of typical urothelial carcinoma. Malignant lesions that should be included in the differential diagnosis of a primary adenocarcinoma of the bladder include noninvasive and invasive urothelial carcinoma with glandular differentiation and secondary malignancies involving the bladder by direct extension or metastasis. The recognition and distinction of these different entities may be a challenge for pathologists, but they are of great clinical importance.

OBJECTIVE

To review features of primary bladder adenocarcinoma as well as those entities that need to be differentiated from primary bladder adenocarcinoma, with emphasis on clinical findings, pathologic characteristics, and immunoprofiles.

DATA SOURCES

Selected original articles published in the PubMed service of the US National Library of Medicine.

CONCLUSIONS

The accurate diagnosis of adenocarcinoma of the urinary bladder is important and challenging. It has to prompt an extensive clinical workup to rule out other glandular lesions in the urinary bladder, especially the possibility of secondary involvement of the bladder by an adenocarcinoma from a different site.

Impact of micropapillary urothelial carcinoma variant histology on survival after radical cystectomy

OBJECTIVES

The role of micropapillary urothelial carcinoma (MUC) variant histology as an independent prognostic factor for survival after radical cystectomy has not been studied. Our aim was to examine the impact of MUC on survival.

MATERIALS AND METHODS

A retrospective analysis of prospectively collected data from the University of Southern California (USC) Bladder Cancer Database was performed. Between 1985 and 2008, 1,380 patients underwent radical cystectomy and superextended pelvic lymph node dissection for bladder cancer. All surgical specimens underwent central pathologic review by dedicated genitourinary pathologists. Histologic type was categorized as urothelial carcinoma (UC; n = 1,347) or MUC (n = 33). The outcomes were overall survival (OS) and recurrence-free survival (RFS). The Kaplan-Meier method and Cox proportional regression models were used to analyze survival data.

RESULTS

The median follow-up duration was 10 years (range, 0-25 years). Baseline characteristics were similar between histologic types except MUC was associated with advanced clinical (cTanyN1-3: 2% vs. 9%, P = 0.03) and pathologic (pTanyN1-3: 22% vs. 46%, P = 0.01) TNM stage, multifocality (38% vs. 58%, P = 0.02), and high nuclear grade (83% vs. 97%, P = 0.03). The predicted 5-year OS (61% and 67%, Log rank P = 0.96) and RFS (69% and 58%, Log rank P = 0.33) rates did not differ between patients with UC and MUC. Multivariable analysis showed that histologic type was not independently associated with OS (HR 0.91, 95% CI 0.55-1.49, P = 0.70) or RFS (HR 0.97, 95% CI 0.55-1.73, P = 0.92).

CONCLUSIONS

Outcomes of radical cystectomy for patients with MUC are similar to those with UC when controlling for other clinical and pathologic factors.

Micropapillary urothelial carcinoma: Cytologic features in a retrospective series of urine specimens

Background:

The micropapillary variant of urothelial carcinoma (uPC) is a rare variant of urothelial carcinoma that carries a poor prognosis. Definitive surgery may represent optimal management of low stage tumors. Urine cytology is indispensable in the screening and follow-up of urinary tract cancer. However, cytopathological criteria for diagnosis of uPC and its differentiation from conventional urothelial carcinoma (CUC) are not well-defined.

Materials and Methods:

Twenty-five cases of histologically confirmed micropapillary uPC from 21 patients were compared to 25 cases of histologically confirmed high-grade CUC.

Results:

In uPC cases, cell clusters were identified in 13 of 25 specimens from 10 patients. Six of the 13 specimens containing cell clusters corresponded to surgical pathology specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. In contrast, only 1 of the 12 urine specimens devoid of cell clusters corresponded to surgical specimens in which micropapillary carcinoma accounted for at least 50% of total carcinoma. Cytomorphologic features of urinary specimens from patients with histologically confirmed micropapillary carcinoma were generally similar to those from patients with high-grade CUC, making it difficult to distinguish these entities in exfoliative urine specimens.

Conclusions and Summary:

Further investigation of the core cytopathological characteristics of uPC is warranted to refine its diagnostic criteria by exfoliative urine cytology.

Plasmacytoid variant of bladder cancer defines patients with poor prognosis if treated with cystectomy and adjuvant cisplatin-based chemotherapy

Background

Since the definition of different histologic subtypes of urothelial carcinomas by the World Health Organization (WHO) 2004 classification, description of molecular features and clinical behavior of these variants has gained more attention.

Methods

We reviewed 205 tumor samples of patients with locally advanced bladder cancer mainly treated within the randomized AUO-AB05/95 trial with radical cystectomy and adjuvant cisplatin-based chemotherapy for histologic subtypes. 178 UC, 18 plasmacytoid (PUC) and 9 micropapillary (MPC) carcinomas of the bladder were identified. Kaplan Meier analysis and backward multivariate Cox’s proportional hazards regression analysis were performed to compare overall survival between the three histologic subtypes.

Results

Patients suffering from PUC have the worst clinical outcome regarding overall survival compared to conventional UC and MPC of the bladder that in turn seem have to best clinical outcome (27.4 months, 62.6 months, and 64.2 months, respectively; p=0.013 by Kaplan Meier analysis). Backward multivariate Cox´s proportional hazards regression analysis (adjusted to relevant clinicopathological parameters) showed a hazard ratio of 3.2 (p=0.045) for PUC in contrast to patients suffering from MPC.

Conclusions

Histopathological diagnosis of rare variants of urothelial carcinoma can identify patients with poor prognosis.

[Micropapillary urothelial carcinoma of the urinary bladder: report of one case and review of the literature.]

In 1994 Amin et al. described an uncommon variant of urothelial carcinoma: the micropapillary carcinoma (MPC) .The MPC of the urinary bladder is rare, but has an aggressive clinical course. The optimal treatment strategy for this tumor appears to be early radical cystectomy. We report a case of MPC of the urinary bladder and review the literature.

Micropapillary carcinoma of the bladder presented with spontaneous intraperitoneal bladder rupture

Spontaneous bladder perforation is a rare presenting feature of bladder malignancy. We describe an unusual case of a patient, admitted to emergency, with diffuse abdominal pain due to spontaneous bladder rupture in association with a micropapillary carcinoma. A diagnosis of an intraperitoneal bladder perforation was made during an emergency operation. Aspects of etiology, clinical presentation, diagnosis and management are described. Although cases of spontaneous carcinomatous bladder rupture are associated with high morbidity and mortality, prompt identification and treatment can lead to favourable outcomes.

Current treatment of metastatic bladder cancer and future directions

Metastatic urothelial carcinoma portends a very poor long-term prognosis, with 5-year survival at approximately 5%. The overall survival of metastatic bladder cancer has not improved over the last 20 years. The first-line therapy is cisplatin-based chemotherapy with the response rate approximately 50%. Approximately 30-50% of the patients are unsuitable for cisplatin, and there is no standard of care for this patient population. There is no standard second-line treatment. Several signaling pathways are activated in bladder urothelial carcinoma, but no targeted therapy, either alone or in combination with conventional cytotoxic chemotherapy, has been shown to significantly improve the treatment outcomes. The future of metastatic urothelial carcinoma treatment lies in the ability to deliver personalized therapy. This area remains an active research field today.

Urothelial carcinoma of the bladder: definition, treatment and future efforts

The identification of patients with high-risk bladder cancer is important for the timely and appropriate treatment of this lethal disease. The understanding of the natural history of bladder cancer has improved; however, the criteria used to define high-risk disease and the relevant treatment strategies have remained the same for the past several decades, despite multiple large, randomized, prospective clinical trials that have evaluated the use of intravesical, surgical and systemic therapies. The genetic signature of high-risk bladder cancer has been a focus of investigation and has led to the discovery of potential molecular targets for disease identification, risk stratification and therapy. These advances, combined with a comprehensive risk assessment profile that incorporates available pathological and clinical characteristics, might improve the diagnosis and treatment of patients with bladder cancer.

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.

Neoadjuvant systemic therapy or early cystectomy? Single-center analysis of outcomes after therapy for patients with clinically localized micropapillary urothelial carcinoma of the bladder

OBJECTIVES

To analyze the treatment outcomes of patients with micropapillary bladder cancer (MPBC). MPBC is a rare variant of urothelial carcinoma with aggressive clinical behavior. Radical cystectomy is considered the standard approach for treatment of patients with localized disease; however, the role of perioperative systemic therapy has been poorly defined.

MATERIAL AND METHODS

A retrospective review identified 38 consecutive patients who had been treated at our institution for MPBC from 2000 to 2010. The patient data were analyzed for the pre- and postoperative clinicopathologic features, treatment course, and cancer-specific survival.

RESULTS

The median follow-up of surviving patients after cystectomy was 17 months (range 2-75). At the initial transurethral biopsy, 28 patients (74%) had clinical Stage T2N0 or less. In this group, 26 (93%) of 28 were upstaged to nonorgan-confined and/or lymph node-positive disease. Overall, 32 patients (86%) had evidence of lymph node metastasis on the final pathologic examination. All patients with cTis-T1 who had undergone initial bladder-sparing therapy with bacille Calmette-Guérin had pathologically advanced disease at cystectomy. All 15 patients who had received perioperative cisplatin-based chemotherapy died of metastatic disease. The 5-year overall survival rate was 40% (95% confidence interval 16-64).

CONCLUSIONS

MPBC is an aggressive disease with a high likelihood of regional lymph node metastasis at the initial presentation. Although radical cystectomy plays a critical role in treatment, systemic neoadjuvant chemotherapy might be a more appropriate strategy than immediate cystectomy. Because of the poor response to current chemotherapy agents, the development of new and effective drugs for this subset of patients could be needed.

Invasive micropapillary carcinoma of the ampulla of Vater with extensive lymph node metastasis: Report of a case

Invasive micropapillary carcinoma is characterized by extensive lymph node metastasis and a poor prognosis. This histological variant was first described in breast cancer, with a few subsequent reports of it in the ampullo-pancreato-biliary region. We report a case of invasive micropapillary carcinoma of the papilla of Vater. A 53-year-old man was admitted to our hospital with signs of obstructive jaundice. Detailed investigations revealed a tumor in the periampullary region, and pancreatoduodenectomy was performed for cancer of the ampulla of Vater. Microscopic examination of the resected specimen revealed a tumor composed mainly of carcinoma cells arranged in micropapillary structures, with extensive regional lymph node metastasis. The patient had an uneventful postoperative course and was followed up in the outpatient clinic. Tumor recurrence with progressive ascites and hydronephrosis was found 8 months after surgery, and the patient died of the disease 20 months after surgery.

Emerging concepts in micropapillary urothelial carcinoma

Micropapillary urothelial carcinoma is a relatively uncommon variant of urothelial carcinoma, but its recognition carries important prognostic and treatment implications. Micropapillary morphology occurs in neoplasms arising in many different organ systems and displays aggressive biologic behavior regardless of its site of origin. On account of this association, micropapillary features in urothelial carcinoma should be reported regardless of whether the pattern is focal or dominant. The overall prognosis for micropapillary urothelial carcinoma is poor and recent studies suggest that early treatment with cystectomy could improve outcome, as these tumors are unlikely to respond to chemotherapy when used as a secondary treatment modality. This review discusses the histologic features required for diagnosis and the clinical significance of rendering a diagnosis of micropapillary urothelial carcinoma.