Small-cell carcinoma of the urinary bladder. A clinico-pathological study of ten cases

HER2 Expression in Bladder Cancer: A Focused View on Its Diagnostic, Prognostic, and Predictive Role

Bladder cancer (BC) is a heterogeneous disease from a molecular, morphological, and clinical standpoint. HER2 is a known oncogene involved in bladder carcinogenesis. Assessing HER2 overexpression as a result of its molecular changes in a routine pathology practice using immunohistochemistry might be a useful adjunct in several scenarios, namely (1) to correctly identify flat urothelial lesions and inverted urothelial lesions in the diagnostic setting; (2) to provide prognostic hints in both non-muscle invasive (NMI) and muscle invasive (MI) tumors, thus supplementing risk stratification tools, especially when evaluating higher-risk tumors such as those with variant morphology; (3) to improve antibody panels as a surrogate marker of BC molecular subtyping. Furthermore, the potential of HER2 as a therapeutic target has been only partly explored so far, in light of the ongoing development of novel target therapies.

Bladder Cancer: A Comparison Between Non-urothelial Variant Histology and Urothelial Carcinoma Across All Stages and Treatment Modalities

BACKGROUND

The purpose of this study was to evaluate stage at presentation, treatment rates, and cancer-specific mortality (CSM) of non-urothelial variant histology (VH) bladder cancer (BCa) relative to urothelial carcinoma of the urinary bladder (UCUB).

MATERIALS AND METHODS

Within the Surveillance, Epidemiology, and End Results registry (SEER, 2004-2016), patients with VH BCa and UCUB were identified. Stage at presentation and treatment rates, as well as multivariably adjusted and matched CSM rates according to TNM stage within each histologic subtype, were reported.

RESULTS

Of all 222,435 eligible patients with BCa, 11,147 (5.0%) harbored VH. Among those, squamous cell carcinoma accounted for 3666 (1.6%) patients, adenocarcinoma for 1862 (0.8%), neuroendocrine carcinoma for 1857 (0.8%), and other VH BCa for 3762 (1.7%) of the study cohort. Patients with VH BCa showed invariably more advanced TNM stage at presentation compared with patients with UCUB. Treatment rates according to TNM stages showed similar distribution of cystectomy rates in VH BCa and UCUB. However, important differences in the distribution of radiotherapy and chemotherapy rates existed within VH BCa and in comparison with UCUB. Furthermore, even after multivariable adjustment and matching with UCUB, squamous cell carcinoma exhibited higher CSM (hazard ratios, 1.43-1.95; all P < .01) across all stages. All other VH predominantly exhibited higher CSM than UCUB in either non-muscle-invasive or muscle-invasive nonmetastatic stages.

CONCLUSION

TNM stage at diagnosis is invariably more advanced in all patients with VH BCa versus patients with UCUB. Of all VH BCa, in multivariably adjusted stage for stage analyses, squamous cell carcinoma appears to have the worst natural history. All other VH subgroups exhibited more aggressive natural history than UCUB in nonmetastatic stages only.

Primary small cell carcinoma of the urinary bladder

Small cell carcinoma of the urinary bladder (SCCB) is an extremely rare but aggressive tumour constituting less than 0.7% of all urinary bladder tumours. It is often misdiagnosed as transitional cell carcinoma, owing to the similarities in presentation. Diagnosis of SCCB is based on the WHO criteria for small cell lung carcinoma. A 58-year-old man who had presented with haematuria and burning micturition for 3 months was initially diagnosed as high-grade muscle-invasive urothelial carcinoma based on the TURBT specimen. The patient was put on neoadjuvant chemotherapy, but presented again with haematuria and back pain after 3 months. Imaging studies showed a lesion in the posterolateral wall of the urinary bladder, along with partial collapse and anterior wedging of L1 vertebra. He underwent TURBT, and on the basis of histopathology and immunohistochemistry, a diagnosis of primary SCCB bladder with vertebral metastasis was made.

The oncological outcomes of small cell carcinoma of the bladder

INTRODUCTION

Small cell carcinoma of the bladder (SmCC) is a rare and aggressive genitourinary malignancy. The paucity of clinical trials and outcome data provide no standard treatment guidelines. Accordingly, patient prognosis is poor. Our goal was to present the first comprehensive in-depth analysis of SmCC in a tertiary Canadian centre.

METHODS

We retrospectively reviewed all patients diagnosed with primary SmCC at the London Regional Cancer Program between January 1990 and 2016. The primary outcome was overall survival (OS). We examined a number of secondary outcomes and baseline characteristics.

RESULTS

We identified 15 men and six women (median age 72 years) with a SmCC diagnosis (median followup 11.33 months). Median Charlson Comorbidity Index score was 7 (interquartile range [IQR] 5-10) and 15 patients had a smoking history. Most common presentation was gross hematuria (18 patients, 86%), and pT2 stage at transurethral resection of the bladder tumour (TURBT) (n= 7/21, 33%), although five patients had cT4 (24%). Pure SmCC was found in nine individuals (43%), whereas 12 had mixed differentiation (57%). From initial staging, 15 patients had extravesical disease (71%), 10 had positive pelvic lymphadenopathy (48%), and distant metastases occurred in six (29%). In our series, five individuals (24%) underwent cystectomy, 18 (86%) received radiation, and 14 (67%) received adjuvant chemotherapy. The median OS was 15 months (two-year OS was 19%).

CONCLUSIONS

SmCC is a rare and aggressive form of bladder cancer. Despite multimodal therapy, prognosis remains guarded, with little improvement seen over the study's 25-year duration. An understanding of study limitations is warranted in interpretation of results.

Clinicopathologic and Immunohistochemical Study of Combined Small Cell Carcinoma and Urothelial Carcinoma Molecular Subtype

Muscle invasive bladder cancer, an aggressive disease with heterogeneous molecular profiles, has recently been subclassified into three major molecular subtypes -basal, luminal and "p53-like" urothelial carcinomas (UCas), which bear prognostic and therapeutic implication. Similar to breast cancer, basal and luminal subtype UCas are designated by basal (CK5/14) and luminal (CK20) markers. The "p53-like" subtype presents with wild-type p53 gene with upregulated p53 pathways and is implicated in chemoresistance. Urinary bladder is one of the most common primary sites of extrapulmonary small cell carcinoma (SmCC). Bladder SmCC frequently coexists with UCa; however, the relation of SmCC with specific UCa molecular subtypes has not been studied. The aim of this study is to investigate the clinicopathology and immunophenotypes of the combined SmCC and UCa molecular subtypes. A total of 22 combined SmCC and UCa cases were studied for the clinicopathology and immunohistochemical (IHC) profiles by luminal and basal cell markers as well as Her2/Neu and p53. Our results demonstrated that all the urinary bladder SmCCs were associated with high grade UCas. They were more commonly seen in older male patients with a smoking history and had a poor prognosis. Based on the reported molecular subtyping, the UCas could be immunohistochemically subclassified into luminal, basal, dual and null types, which showed different clinicopathologic and IHC features. Compared to non-SmCC associated UCa, the subtypes of UCa in the combined SmCCs and UCas were characterized by: 1) Although overall luminal type was still relatively more common in men, basal marker-expressing subtypes were significantly increased in incidence and were more common in women. 2) Her2/Neu overexpression was more commonly observed in luminal than basal cell marker-expressing UCas. 3) IHC overexpression of p53 was common in all the subtypes, with UCas and SmCCs sharing the same p53 expression pattern. Although limited by relatively a small number of cases, the results of this study will enhance our understanding of the combined SmCC and UCa entity and potentially lead to a future therapeutic management.

Small-cell carcinoma of the urinary bladder: where do we stand?

Small-cell carcinoma of the urinary bladder is a very rare pathology, but with a very aggressive behavior and disappointing prognosis. The literature concerning this type of cancer is scarce and physicians may encounter difficulty trying to manage it. Most articles involve the study of case series, without definite results due to the small number of patients. The present article aims at gathering the most significant articles and results in order to offer a broad perspective on the existing literature concerning this pathology.

Small Cell Carcinomas of the Bladder Highly Express Somatostatin Receptor Type 2A: Impact on Prognosis and Treatment--A Multicenter Study of Urooncology Society, Turkey

Small cell carcinoma (SmCC) is a rare and aggressive neuroendocrine carcinoma of the bladder. Neuroendocrine carcinomas expressing somatostatin receptors (SSTR) in other viscera such as lung, pancreas, and gastrointestinal system respond to therapy with somatostatin analogs. In the present study, expressions of SSTRs 1 to 5 including type 2A are investigated by immunohistochemistry (IHC) and their relationship with clinicopathologic factors was evaluated. Hundred primary bladder SmCC cases were collected from 12 centers in Turkey. Forty-three cases were pure SmCC. Other cases had mostly papillary urothelial carcinoma as a second component. The percentage of the SmCC component ranged from 5% to 100%. SSTR-2A expression was membranous, whereas the other receptors showed cytoplasmic staining. The percentages of positive cases for SSTR-1, SSTR-2A, SSTR-3, SSTR-4, and SSTR-5 were 4% (3/75), 61.4% (54/88), 2.4% (2/84), 24.4% (20/82), and 6.25% (5/80), respectively. The percentage of SmCC component was positively correlated with the percentage of SSTR-2A expression (P=0.003) while negatively correlated with patient age (P=0.032). SSTR-2A expression was correlated with survival as a bad prognostic factor (P=0.018). SSTR-1, SSTR-3, SSTR-4, and SSTR-5 expressions did not show any statistical significance with any parameter. In conclusion, although the limited number of cases with adequate term follow-up, SSTR-2A expression could be a prognostic factor and somatostatin analogs therapeutic candidate for SmCCs of the bladder as these tumors show high percentage of SSTR-2A expression.

Neuroendocrine Tumors of the Urinary Bladder According to the 2016 World Health Organization Classification: Molecular and Clinical Characteristics

Neuroendocrine neoplasms of the urinary bladder are a rare type of tumor that account for a small percentage of urinary bladder neoplasms. These tumors of the urinary bladder range from well-differentiated neuroendocrine neoplasms (carcinoids) to the more aggressive subtypes such as small cell carcinoma. Despite the rarity of the neuroendocrine tumors of the bladder, there has been substantial investigation into the underlying genomic, molecular, and the cellular alterations within this group of neoplasms. Accordingly, these findings are increasingly incorporated into the understanding of clinical aspects of these neoplasms. In this review, we provide an overview of recent literature related to the 2016 World Health Organization Classification of Neuroendocrine Tumors of the Urinary Bladder. Particular emphasis is placed on molecular alterations and recently described gene expression. The neuroendocrine tumors of the urinary bladder are subdivided into four subtypes. Similar to their pulmonary and other extrapulmonary site counterparts, these have different degrees of neuroendocrine differentiation and morphological features. The clinical aspects of four subtypes of neuroendocrine tumor are discussed with emphasis of the most recent developments in diagnosis, treatment, and prognosis. An understanding of molecular basis of neuroendocrine tumors will provide a base of knowledge for future investigations into this group of unusual bladder neoplasms.

Small cell carcinoma of the urinary bladder: changing trends in the current literature

Background Extrapulmonary small cell carcinoma (SmCC), also known as oat cell carcinoma or small cell neuroendocrine carcinoma, is characterized by an aggressive clinical course with early metastasis pattern and a short life expectancy. So far, there is no prospective, data-based case-control study due to its low incidence. The purpose of this paper is to discuss the epidemiology, morphopathology, clinical characteristics, differential diagnosis and treatment of bladder SmCC in the light of the literature. Scope PubMed and American Society of Clinical Oncology Meeting abstracts were searched according to the following keywords: 'extrapulmonary SmCC', 'bladder cancer', and 'therapeutic approach'. The last search was performed on 1 October 2015. Some additional papers were determined by reviewing references of the appropriate articles. Most of the data regarding small cell carcinoma of the urinary bladder (SmCCB) were found to be based on the retrospective trials. Findings Bladder SmCC is more frequent in men and usually appears in the seventh to eighth decades. Macroscopic hematuria is the most common clinical symptom. The diagnosis of SmCCB is performed based on the same criteria determined by the WHO classification for the diagnosis of small cell lung carcinoma (SCLC). Prognosis is closely correlated with the stage at presentation. Although the prognosis of the disease is poor, a long survival can be achieved particularly by radical surgery following neoadjuvant chemotherapy in patients with early stage tumors. Cystectomy is still the current standard local treatment. However, cystectomy alone is not sufficient. Chemotherapy and definitive radiotherapy should be preferred for limited disease in patients who are not candidate for surgery. Conclusion Considering the poor prognosis of the disease, further studies are needed to determine the optimal treatment options and new molecular markers in the way of early diagnosis and favorable outcomes. Prospective, multicenter, randomized studies are required to evaluate the role of neoadjuvant chemotherapy followed either by surgery or radiotherapy.

Small cell carcinoma of the urinary bladder without gross hematuria: a case report

Small cell carcinoma of the urinary bladder (SCCB) is a rare and aggressive form of bladder cancer with poor prognosis. Hematuria is the main symptom of this malignancy, and most patients have a history of smoking. The disease incidence of malignant bladder tumors in China is approximately 0.74%. Early and accurate diagnosis of SCCB can ensure timely and appropriate treatment of this malignant disease. Oncologic surgery is the standard treatment; however, it may not be a curative approach. Chemotherapy and/or radiotherapy should be performed following surgical removal. This case report describes a patient with a single neoplasm diagnosed as SCCB that arose because of recurrence of bladder cancer after bladder tumor resection. In contrast to previously reported cases, this patient had no gross hematuria and no history of smoking.

Immunohistochemical evaluation of novel and traditional markers associated with urothelial differentiation in a spectrum of variants of urothelial carcinoma of the urinary bladder

Data on immunohistochemical expression of novel and traditional urothelial markers in the wide range of urothelial carcinoma variants have so far been very limited. In this study, whole tissue sections from 130 bladder urothelial carcinoma and variants were stained with a panel of novel and traditional immunomarkers supportive of urothelial lineage. The positivity rates were as follows: (a) urothelial carcinomas with or without divergent differentiation: GATA3 (50%), S-100P (86%), uroplakin III (20%), thrombomodulin (40%), cytokeratin 7 (CK7) (80%), CK20 (55%), p63 (87%), and high molecular weight cytokeratin (HMCK) (89%); (b) urothelial carcinoma variants (micropapillary, plasmacytoid, nested, clear cell, and microcystic): GATA3 (88%), S-100P (96%), uroplakin III (33%), thrombomodulin (49%), CK7 (95%), CK20 (61%), p63 (69%), and HMCK (96%); and (c) undifferentiated carcinomas (lymphoepithelioma-like carcinoma, small cell carcinoma, sarcomatoid carcinoma and carcinoma with rhabdoid and giant cells): GATA3 (28%), S-100P (31%), uroplakin III (0%), thrombomodulin (22%), CK7 (50%), CK20 (3%), p63 (50%), and HMCK (49%). In urothelial carcinoma with squamous differentiation, GATA3 expression was lower (20%) in contrast to p63 and S-100P. In urothelial carcinoma with glandular differentiation, GATA3 (50%) and p63 (60%) expression was lower than S-100P (100%). p63 expression was relatively lower in micropapillary (54%) and plasmacytoid (50%) variants compared with the other urothelial carcinoma variants. This study provides comprehensive data for novel and traditionally used markers to support urothelial lineage in urothelial carcinoma variants. Our findings show that GATA3, S-100P, CK7, CK20, HMCK, and p63, in the appropriate differential diagnostic setting, are useful to support urothelial lineage of variant morphologies.

Neuroendocrine carcinoma of the urinary bladder: a retrospective study of CT findings

PURPOSE

The purpose of this study was to evaluate the radiographic features of neuroendocrine carcinoma of the urinary bladder (NECB) on CT and to review the literature regarding carcinogenesis, treatment, and prognosis.

METHODS

The presenting CT of patients with pathology-proven NECB were retrospectively reviewed for features including size and appearance of the bladder mass, the presence of hydronephrosis, bladder wall thickening, invasion of perivesical fat, lymph nodes, and distant metastasis. Follow-up imaging and the medical record were reviewed to determine patient treatment and overall survival.

RESULTS

Sixteen patients (13 males, 3 females) were diagnosed with NECB with a mean age of 75.5 years (range 48-90). The characteristic CT appearance was a large polypoid bladder mass (average size 4.9 cm). Extension into the perivesical fat, adjacent organ involvement, and distant metastases were common.

CONCLUSION

NECB is an aggressive primary neoplasm of the bladder that presents on CT as a large bladder mass with local extension into the perivesical fat, involvement of adjacent organs, and metastasis.

Clinical outcome of primary small cell carcinoma of the urinary bladder

Purpose

Primary small cell carcinoma of the urinary bladder is a rare malignant disease. It accounts for less than 1% of all urinary bladder carcinomas. The purpose of this study is to review the clinical features, the treatment modalities, and the overall survival of these patients. We also compare the clinical outcomes between patients of bladder small cell carcinoma (SCC) and bladder urothelial carcinoma (UC).

Materials and methods

We reviewed the charts of patients with bladder tumors from January 1995 to December 2012 in the Chang Gung Memorial Hospital. A total of 2421 malignant bladder tumor patients were reviewed and there were 18 patients who were diagnosed with primary bladder SCC. The patients’ characteristics, including age, gender, smoking history, presented symptoms, tumor size, locations, clinical stages, treatment modalities, pathology appearance, recurrence conditions, and survival conditions were all recorded. We also compared the clinical outcomes and the overall survival rates between patients with bladder SCC and those with UC.

Results

Bladder SCC accounted for about 0.74% of all bladder malignancies in our institution. The mean age at diagnosis was 70.67 years, and the male-to-female ratio was 2.6:1. Thirteen patients had a history of cigarette smoking. All patients presented with symptoms of gross hematuria, and three of them had bladder tamponade requiring blood clot evacuation by cystoscopy. Only one patient had T1 disease, ten patients had stage III disease, and seven patients had lymph node or distant metastasis (stage IV disease). The mean tumor size was 4.29 cm in diameter. For the majority (61.11%) of patients, SCC coexisted with UC components. The average survival time was 10.92 months. Patients with bladder SCC had worse overall survival rates than those of stage III and stage IV bladder UC. Performing radical cystectomy does not significantly improve their overall survival rates. None of the clinicopathologic parameters, including the presence of coexisting nonsmall cell carcinoma component (P = 0.831), receiving radical cystectomy (P = 0.194), distant metastasis (P = 0.062), and gender (P = 0.564), were significantly associated with survival.

Conclusion

SCC of the urinary bladder is a rare condition, and standard treatment outlines have not been well established. Most of the presented cases have a very poor prognosis. Prospective, multi-institutional, randomized studies are required to assess better treatment modalities. To the best of our knowledge, this is the largest reported case analysis of primary bladder SCC in a Taiwanese population.

Value of thyroid transcription factor-1 immunostaining in tumor diagnosis: a review and update

Thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor that plays a critical role in the normal development of embryonic epithelial cells of the thyroid and lung. Because TTF-1 expression is highly restricted to epithelial tumors arising in these organs, it is, at present, one of the immunohistochemical markers most commonly used to assist in the differential diagnosis of carcinomas of the lung and thyroid. Recent studies, however, have reported that TTF-1 is not as specific for lung and thyroid carcinomas as was previously thought as it can be found to be expressed, although much less frequently, in some carcinomas arising in other organs, such as the ovaries, endometrium, colon, and breast, as well as in some tumors of the central nervous system. Even though this unexpected TTF-1 positivity has been reported more frequently with the recently available SPT24 anti-TTF-1 monoclonal antibody, it has also been shown to occur with the commonly used 8G7G3/1 clone, albeit in a lower percentage of cases. Despite these findings, TTF-1 remains a very useful immunohistochemical marker in diagnostic pathology.

Small cell carcinoma of the urinary bladder: a rare, aggressive neuroendocrine malignancy

Small cell carcinoma of the urinary bladder is a rare, often fatal, disease. Its presenting symptoms and gross morphology are similar to those of conventional urothelial carcinoma, whereas its prognosis is much poorer with frequent metastasis. Small cell carcinoma of the urinary bladder shares similar histology with its counterparts in other organs; however, its immunoreactivity to conventional neuroendocrine markers is low. Its diagnosis is thus considered permissible on morphologic grounds alone. Multimodal treatments are often employed, although no definite treatment algorithm has been established. For this extremely aggressive malignancy with an as-yet inconclusive etiology, further studies are needed to clarify its molecular pathogenesis to serve as a basis for diagnostic markers and therapeutic targets. The clinical, morphologic, immunoreactive, molecular, and therapeutic features of bladder small cell carcinoma are reviewed, including a detailed discussion on the utility of immunohistochemical markers.

A clinical review of small-cell carcinoma of the urinary bladder

Small-cell carcinoma of the urinary bladder is a rare and aggressive type of bladder cancer that has a poor prognosis. The incidence has been gradually increasing because of the aging population. Owing to its rarity there are no available treatment guidelines. Several retrospective studies and 1 prospective study have provided some insight into therapy for this disease. A multimodal approach that includes chemotherapy, local radiation therapy, and definitive surgery in resectable cases appears to be an optimal management approach.

Primary small cell carcinoma of the urinary bladder--mini-review of the literature

Primary small cell carcinoma of urinary bladder is a rare but aggressive disease with poor prognosis and a high mortality rate. It accounts for less than 1 % of all the primary cancers seen in the urinary bladder. Diagnosis and management of this entity poses a challenge to the clinician due to the lack of a standardized protocol for its treatment. Herein we discuss primary small cell carcinoma of the urinary bladder in its entirety.

Small cell carcinoma of the urinary bladder: a rare tumor with propensity for hepatic involvement

Small cell (neuroendocrine) carcinoma of the bladder is a rare entity, accounting for less than 1% of all bladder tumors. The authors report 2 new cases of the disease, both presenting with liver metastasis. In the first case, small cell carcinoma occurred in an 85-year-old woman as tumor recurrence of previous micropapillary carcinoma and urothelial carcinoma in situ, illustrating the common coexistence with conventional urothelial carcinoma. In the second case of a 58-year-old man, non-small cell tumor components were not observed. Accurate diagnosis of small cell carcinoma may be challenging. A panel of different antibodies, including neuron-specific enolase, chromogranin A, synaptophysin and CD56 (neural cell adhesion molecule) is recommended. In conclusion, small cell carcinoma represents a rare and aggressive form of bladder malignancy. As illustrated by the 2 cases and according to the literature review, the tumor shows a so far underrecognized propensity for hepatic involvement.

Expression of regulatory proteins and proliferative activity in relation to phenotypic characteristics of upper urothelial carcinoma

BACKGROUND/AIM

Deregulation of the normal cell cycle is common in upper urothelial carcinoma (UUC). The aim of this study was to investigate the expression of regulatory proteins of the cell cycle (p53, p16, cyclin D1, HER-2) and proliferative Ki-67 activity in UUC, and to determine their interaction and influence on the phenotypic characteristics of UUC.

METHODS

In 44 patients with UUC, histopathological and immunohistochemical analyses (p53, p16, cyclin D1, HER-2, and Ki-67) of tumors were done.

RESULTS

Overexpression/altered expression of p53, p16, cyclin D1 or HER-2 was detected in 20%, 57%, 64%, and 57% of tumors, respectively. Eleven (25%) UUC had a high proliferative Ki-67 index. Forty patients (91%) had at least one marker altered, while four (9%) tumors had a wild-type status. Analysis of relationship between expressions of molecular markers showed that only high expression of p53 was significantly associated with altered p16 activity (p < 0.05). High Ki-67 index was associated with the high stage (p < 0.005), solid growth (p < 0.01), high grade (p < 0.05), and multifocality p < 0.05) of UUC, while high expression of p53 was associated with the solid growth (p < 0.05). In regression models that included all molecular markers and phenotypic characteristics, only Ki-67 correlated with the growth (p < 0.0001), stage (p < 0.01), grade (p < 0.05) and multifocality (p < 0.05) of UCC; (Ki-67 and HER-2 expression correlated with the lymphovascular invasion (p < 0.05).

CONCLUSIONS

This investigation showed that only negative regulatory proteins of the cell cycle, p53 and p16, were significantly associated in UUC, while proliferative marker Ki-67 was in relation to the key phenotypic characteristics of UUC in the best way.

HNK-1 glycan functions as a tumor suppressor for astrocytic tumor

Astrocytic tumor is the most prevalent primary brain tumor. However, the role of cell surface carbohydrates in astrocytic tumor invasion is not known. In a previous study, we showed that polysialic acid facilitates astrocytic tumor invasion and thereby tumor progression. Here, we examined the role of HNK-1 glycan in astrocytic tumor invasion. A Kaplan-Meier analysis of 45 patients revealed that higher HNK-1 expression levels were positively associated with increased survival of patients. To determine the role of HNK-1 glycan, we transfected C6 glioma cells, which lack HNK-1 glycan expression, with β1,3-glucuronyltransferase-P cDNA, generating HNK-1-positive cells. When these cells were injected into the mouse brain, the resultant tumors were 60% smaller than tumors emerging from injection of the mock-transfected HNK-1-negative C6 cells. HNK-1-positive C6 cells also grew more slowly than mock-transfected C6 cells in anchorage-dependent and anchorage-independent assays. C6-HNK-1 cells migrated well after treatment of anti-β1 integrin antibody, whereas the same treatment inhibited cell migration of mock-transfected C6 cells. Similarly, α-dystroglycan containing HNK-1 glycan is different from those containing the laminin-binding glycans, supporting the above conclusion that C6-HNK-1 cells migrate independently from β1-integrin-mediated signaling. Moreover, HNK-1-positive cells exhibited attenuated activation of ERK 1/2 compared with mock-transfected C6 cells, whereas focal adhesion kinase activation was equivalent in both cell types. Overall, these results indicate that HNK-1 glycan functions as a tumor suppressor.

TTF1 expression in normal lung neuroendocrine cells and related tumors: immunohistochemical study comparing two different monoclonal antibodies

Thyroid transcription factor-1 (TTF1) regulates lung morphogenesis and differentiation, and its immunohistochemical expression is used for identifying lung neoplasms. The 8G7G3/1 antibody has been used in previous studies, but a different and more sensitive anti-TTF1 antibody, named SPT24, has become commercially available. Since the immunohistochemical expression of TTF1 in normal lung neuroendocrine (NE) cells has not been previously investigated and its utility in the diagnosis of lung NE tumors is a controversial issue, we studied the TTF1 expression in normal adult and fetal lungs, in 83 pulmonary NE neoplasms, in 131 non-lung NE tumors and in 36 metastases from these neoplasms using these two antibodies. A TTF1 immunoreactivity was demonstrated in normal fetal and adult NE cells when using the SPT24 clone. Conversely, using the 8G7G3/1 antibody, only rare fetal neuroendocrine cells were TTF1 positive while adult NE cells were negative. The SPT24 clone identified TTF1 expression in more carcinoids, most of them peripherally located, and poorly differentiated NE carcinomas than the 8G7G3/1 clone. Non-pulmonary well-differentiated NE tumors were negative for both antibodies. Among the 45 non-pulmonary poorly differentiated NE carcinomas 11% were positive for 8G7G3/1 and 18% for SPT24. TTF1 expression in metastases perfectly reflected that detected in the related primary tumors. Our results indicate that the SPT24 antibody is more sensitive than the 8G7G3/1 clone for labeling lung carcinoids and it appears particularly useful in detecting peripheral neoplasms. In addition, the expression of TTF1 in normal NE cells suggests a possible role for the transcription factor in their development and differentiation.

Symptomatic brain metastases from small-cell carcinoma of the urinary bladder: The Netherlands Cancer Institute experience and literature review

BACKGROUND

The incidence of symptomatic brain metastases in small-cell carcinoma of the urinary bladder (SCBC) is unknown. This precludes advice about prophylactic cranial irradiation (PCI).

PATIENTS AND METHODS

The medical records of all patients with SCBC seen at The Netherlands Cancer Institute from 1993 to 2009 (n = 51) were reviewed. Limited disease (LD) was defined as any pT, cN₀₋₁, and cM₁. Patients with LD were offered bladder-preserving treatment involving combined chemoradiotherapy. Patients with extensive disease (ED) were treated with palliative chemotherapy. PCI was not applied in any patient.

RESULTS

Among 39 patients with LD, median disease-specific survival was 35 months. Four developed symptomatic brain metastases after a median follow-up of 15 months (range 3-24) and were treated with whole-brain radiotherapy. No patient with ED developed symptomatic brain metastases during a median follow-up of 6 months. The reported incidence of brain metastases in SCBC in the literature ranges between 0% and 40%. On the basis of all reported series, the pooled estimate of the cumulative incidence of brain metastases is 10.5% (95% confidence interval 7.5% to 14.1%).

CONCLUSIONS

The incidence of symptomatic brain metastases from SCBC is significantly lower than that from small-cell lung cancer. Therefore, we do not routinely advise PCI in patients with SCBC.

Inverse p16 and p63 expression in small cell carcinoma and high-grade urothelial cell carcinoma of the urinary bladder

Small cell carcinoma (SmCC) of the urinary bladder is a rare, highly aggressive neoplasm. The diagnosis is usually made on morphologic grounds, with the help of immunohistochemistry to document neuroendocrine differentiation. However, neuroendocrine markers generally have low sensitivity, ranging between 30-70%. Recent studies have reported p16 over-expression in SmCC of the lung, suggesting that p16 immunohistochemistry may be useful in the diagnosis of bladder SmCC. This is the first study to analyze the usefulness of p16 in the distinction of small cell and high grade urothelial cell carcinoma (HG-UCC). Fourteen cases of SmCCs and sixteen cases of HG-UCC of the bladder were stained with p16, p63, cytokeratin 20 (CK20), cytokeratin 7 (CK7), chromogranin (Chr), synaptophysin (Syn), and CD56. P16 expression was significantly higher in SmCCs (92.8%) when compared to HG-UCCs (43.7%). P63 and CK20, on the other hand, were positive in the majority of HG-UCCs (81.3% and 50%, respectively), while only 14.3% of SmCCs showed focal immunoreactivity with CK20. The sensitivity of the traditional neuroendocrine markers was low, ranging between 28.6% (Chr) and 71.4% (CD56) in SmCCs. P16 positivity in the absence of p63 and CK20 is highly characteristic of SmCC, while p63 and CK20 positivity with or without p16 expression is typical of HG-UCC.

Urothelial Carcinoma and its Variants

Bladder cancer is the ninth most common cancer worldwide, and the most common malignancy affecting the urinary tract, with approximately 330,000 new cases and more than 130,000 deaths per year. Bladder cancer is primarily attributable to smoking, which accounts for 65% of male and 30% of female cases in some developed countries. Other major risk factors include analgesic abuse, some types of chemotherapy, occupational exposure to chemicals, and in Egypt and some Asian regions, endemic infection with Schistosoma haematobium. Approximately 90% of bladder tumors are classified as urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), and are believed to originate from transformation of the normal urothelium. UCs often exhibit elements of squamous or glandular differentiation. The spectrum of microscopic forms of urothelial carcinoma has been expanded recently to include several histologic variants, the recognition of which is important to avoid diagnostic misinterpretation, to predict outcome, and to guide the selection of the most appropriate therapeutic approach. This article reviews characteristic pathologic features and key clinical aspects of UC and its most common variants.

Small cell carcinoma of the urinary bladder--histogenesis, genetics, diagnosis, biomarkers, treatment, and prognosis

Small cell carcinoma of the urinary bladder is a rare but highly aggressive malignancy with a dismal prognosis. Most patients present with advanced disease at the time of diagnosis. Hematuria is the most frequent presenting symptom. Histologically, small cell carcinoma of the urinary bladder is indistinguishable from its pulmonary counterpart. Coexistence with other types of carcinoma is common. Histogenesis is uncertain; there are several competing theories, including origin from stem cells, from urothelial cells, and from neuroendocrine cells in normal or metaplastic urothelium. The molecular pathogenesis remains unclear. Immunohistochemical staining can be extremely helpful in establishing the diagnosis, and in investigating the use of potential therapeutic strategies. Currently, combinations of surgical resection, chemotherapy, and radiation therapy represent the main treatment options. The recent observation of c-kit and epidermal growth factor receptor expression in more than 25% of patients with urinary bladder small cell carcinoma opens new avenues for further investigation. Improvement in survival may depend upon the identification of new molecular markers to facilitate earlier diagnosis and the development of novel targeted therapies. In this paper, we review general aspects of small cell carcinoma of the urinary bladder, focusing on the ways in which our understanding of this entity has been positively influenced by studies of the histopathologic and immunohistochemical findings, and by investigations of genetic alterations in this disease.

The pathology of extrapulmonary small cell carcinoma

Extrapulmonary small cell carcinomas (EPSCCs) are uncommon malignant neoplasms with a reported incidence of 0.1% to 0.4% in the United States. Since their first description in 1930, they have been seen in nearly every organ system. Like their more common pulmonary counterparts, EPSCCs are thought to arise from a multipotential stem cell. However, there is recent molecular evidence that small cell elements may arise as a late-stage phenomenon in the genetic progression of more organ-typical carcinomas. The morphologic, immunohistochemical, and ultrastructural features are similar to those described in pulmonary small cell carcinomas (PSCCs). The differential diagnosis of EPSCC includes PSCC, other neuroendocrine tumors, small round blue cell tumors, metastatic melanoma, lymphoma, and poorly differentiated non-small cell carcinomas. Molecular alterations reported to occur in EPSCCs include abnormalities described in PSCC and changes found in carcinomas more typically encountered in the organ from which they arise. In this article we discuss the pathology of EPSCC with a review of theories of histogenesis, sites of occurrence, diagnostic features, differential diagnosis, molecular alterations, and clinical behavior.

Small-cell carcinoma of the urinary bladder: diagnosis and management

Small-cell carcinoma of the urinary bladder (SCCUB) accounts for less than 1% of all cancers arising in the urinary bladder. Current diagnosis and management of SCCUB are often patterned after small-cell lung cancer (SCLC). However, SCCUB therapy is different from that for SCLC. For example, many patients with SCCUB undergo local resection, which is rarely performed in SCLC. As in SCLC, platinum-etoposide combination chemotherapy is employed as the main systemic treatment option for SCCUB. Chemotherapy is usually combined with other therapeutic modalities, especially in patients whose disease is limited to the locoregional area. Owing to the rarity of this malignancy, no prospective study has been performed that establishes the efficacy and duration of chemotherapy or the relative efficacy of platinum-etoposide versus other chemotherapeutic regimens. This article provides a comprehensive review of the current status of SCCUB diagnosis and management, as well as some unique insights into this rare tumor.

Clinical review – Small cell carcinoma of the bladder

OBJECTIVES

To review the published literature on the diagnosis and management of small cell carcinoma of the bladder (SCCB).

METHODS

Papers were identified by searches of PubMed using the terms "small cell", "bladder" and "carcinoma". Additional papers were identified from review of references of relevant articles.

RESULTS

SCCB comprises less than 1% of bladder malignancies. It is an aggressive tumour that commonly presents at an advanced stage, in an elderly population. Consequently, patients are often not fit for anti-neoplastic therapy. In fit patients, the bedrock of treatment in the majority of cases is platinum-based systemic chemotherapy, which was the only factor predictive of improved outcome on multivariate analysis in one large review. The use of neoadjuvant chemotherapy has been associated with favourable results and may therefore be the preferred approach when scheduling treatment. Options for local management comprise surgery or radiotherapy (sequentially or concurrently with chemotherapy), both of which are potentially curative in selected cases. However, the subsequent frequent development of urothelial malignancies with bladder-sparing approaches should be considered when planning treatment, particularly in younger patients. Prognosis of SCCB overall is poor, the median survival of all cases varies from 4 to 23 months, and overall survival at 5 years from 10% to 40% of patients.

CONCLUSIONS

SCCB is a rare and aggressive tumour with a poor prognosis. Future efforts should be directed at its early detection and the development of more effective systemic therapies.

Primary Small Cell Bladder Carcinoma: A Case Report and Review of the Current Literature

Primary small cell bladder carcinoma is an extremely rare and highly aggressive tumor. Unfortunately, the optimal therapeutic strategy for the tumor is still unknown. Recently, a two-stage system for limited and extensive small cell bladder carcinoma has been suggested in analogy to the practiced staging and treatment of small cell lung carcinoma. We present a new case of small cell bladder carcinoma and discuss relevant current literature.

Small cell carcinoma of the prostate: an immunohistochemical study

Small cell carcinoma of the prostate (SCPC) is morphologically similar to small cell carcinoma of the lung (SCLC) and maybe misinterpreted as Gleason pattern 5b prostate adenocarcinoma (HGPC). Recognition of SCPC is important because of its different clinical behavior. This study aims to characterize the immunophenotype of histologically classic SCPC using a comprehensive panel of markers, to better understand its histogenesis, aid in its classification, and evaluate potential therapeutic targets. Using the World Health Organization morphologic criteria for SCLC, 18 SCPC cases were identified; and studied for the following tumor marker groups: prostate specific/related, neuroendocrine, sex steroid hormone receptors, and prognostic/treatment target-related. Ten cases of UPC were used as controls. PSA was positive in 17% of SCPC and neuroendocrine markers were expressed in HGPC. PSA, TTF-1 and CD56 were the most helpful markers in differentiating between SCPC and HGPC (P<0.01), whereas bombesin/GRP, c-kit, bcl-2, and EGFR expression was more frequent in SCPC. SCPC is best diagnosed by following the World Health Organization diagnostic criteria for SCLC. Immunohistochemical markers can help separate SCPC from HGPC and may be useful in histologically borderline cases. Potential therapeutic targets are identified immunohistochemically in SCPC (Bombesin/GRP, c-kit, bcl-2, and EGFR).