Plasmacytoid Urothelial Carcinoma: An Unusual Variant That Warrants Aggressive Management and Critical Distinction on Transurethral Resections

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.

Molecular characterization of plasmacytoid urothelial carcinoma and the impact on treatment implications

Bladder cancer researchers and clinicians have increasingly viewed tumor biology through the lens of genomic and molecular alterations, drastically improving our knowledge of the underlying disease biology. This understanding has led to significant advances in treatment options that allow implementation of a personalized approach to cancer treatment. Large-scale genomic studies initially focused on the most common forms of bladder cancer. However, as genomic and molecular technologies become more widespread and are applied to less common variant histologies, we are gaining additional insight into the unique molecular and genomic characteristics driving the biology of variant histologies of bladder cancer. In this review, we summarize the current state of knowledge of molecular alterations underlying the distinct tumor biology of plasmacytoid urothelial carcinoma and how these alterations may impact treatment options.

Renal pelvis cancer with initial symptoms of malignant gastric outlet obstruction

Introduction

Gastric outlet obstruction caused by upper tract urothelial carcinoma is rare.

Case presentation

A 78-year-old man presented to the hospital with nausea and vomiting. No hematuria was observed. Computed tomography revealed a tumor in the right renal pelvis and duodenal stenosis. Gastrojejunostomy was performed to treat the symptoms of the gastric outlet obstruction so that the patient could resume oral intake and outpatient chemotherapy. Chemotherapy was unsuccessful, and the patient died 9 months after the gastrojejunostomy. Histological assessment of an autopsy specimen revealed plasmacytoid urothelial carcinoma with direct infiltration of the duodenal wall, which caused the stenosis.

Conclusion

Autopsy revealed a right renal pelvis cancer causing gastric outlet obstruction. Early gastrojejunostomy enabled oral intake and outpatient visits.

Metastatic Plasmacytoid Urothelial Carcinoma Masquerading as a Primary Signet Ring Cell Carcinoma of the Duodenum

Plasmacytoid urothelial carcinoma can histologically mimic gastrointestinal signet ring cell carcinoma, a potential diagnostic pitfall resulting in improper clinical management. We present a rare case of a malignant duodenal ulcer due to metastasis from plasmacytoid urothelial carcinoma. Only by histological and retrospective immunohistochemical comparison with the primary bladder tumor was this revealed as a metastasis from a plasmacytoid urothelial carcinoma. This case report highlights the importance of clinical correlation and comparison with any previous pathology specimens, the limitations of immunohistochemical staining, and the utilization of both old and new immunohistochemical tools when differentiating signet ring cell carcinomas of primary sites versus potential metastases.

Large, Nested Variant of Urothelial Carcinoma Is Enriched with Activating Mutations in Fibroblast Growth Factor Receptor-3 among Other Targetable Mutations

The large, nested variant of urothelial carcinoma (LNVUC) is characterized by bland histomorphology mimicking that of benign von Brunn nests. In the current study, we aimed to investigate the Fibroblast Growth Factor Receptor-3 (FGFR-3) activation and missense mutation in 38 cases, including 6 cases diagnosed with LNVUC and 32 with metastatic invasive urothelial carcinoma (UC). Initially, six formalin-fixed paraffin-embedded (FFPE) tissue samples of the LNVUC were subjected to whole-exome sequencing (WES), and then we performed targeted sequencing on 32 cases of metastatic invasive UC of various morphological subtypes, which were interrogated for the FGFR3. Our results revealed 3/6 (50%) LNVUC cases evaluated by WES in our study showed an activating mutation in FGFR-3, 33% showed an activating mutation in PIK3CA, and 17% showed activating mutation in GNAS or MRE11. Additionally, 33% of cases showed a truncating mutation in CDKN1B. All LNVUC in our study that harbored the FGFR-3 mutation showed additional activating or truncating mutations in other genes. Overall, 6/32 (18.75%) cases of random metastatic invasive UC showed missense mutations of the FGFR-3 gene. The LNVUC variant showed the higher incidence of FGFR-3 mutations compared to other types of mutations. Additionally, all LNVUC cases show additional activating or truncating mutations in other genes, thus being amenable to novel targeted therapy.

Plasmacytoid Variant Urothelial Cell Carcinoma: A Case of a Histological Variant of Urinary Bladder Cancer With Aggressive Behavior

This paper presents a case report of plasmacytoid variant urothelial carcinoma (PVUC), a rare form of transitional cell carcinoma. PVUC is known for its unique clinical features, aggressive behavior, and poor survival rates. PVUC comprises less than 3% of all bladder tumors, and its diagnosis is often difficult due to its resemblance to other forms of bladder cancer. It requires a staging workup to rule out metastasis, relies heavily on immunostaining and histopathological analysis for diagnosis, and requires a multidisciplinary approach with early aggressive treatment, including cisplatin-based chemotherapy following surgery. This report highlights the importance of understanding rare variants of bladder cancer to ensure timely and accurate diagnosis and appropriate treatment planning. We report here a case of a 75-year-old male with multiple comorbidities who presented with hematuria and was diagnosed with urothelial carcinoma plasmacytoid type, which was initially treated with transurethral resection but later found to be unresectable and treated with palliative chemotherapy and radiation therapy. Eventually, the patient passed away three years after the diagnosis.

Urinary Bladder Masses, Rare Subtypes, and Masslike Lesions: Radiologic-Pathologic Correlation

Urinary bladder masses are commonly encountered in clinical practice, with 95% arising from the epithelial layer and rarer tumors arising from the lamina propria, muscularis propria, serosa, and adventitia. The extent of neoplastic invasion into these bladder layers is assessed with multimodality imaging, and the MRI-based Vesical Imaging Reporting and Data System is increasingly used to aid tumor staging. Given the multiple layers and cell lineages, a diverse array of pathologic entities can arise from the urinary bladder, and distinguishing among benign, malignant, and nonneoplastic entities is not reliably feasible in most cases. Pathologic assessment remains the standard of care for classification of bladder masses. Although urothelial carcinoma accounts for most urinary bladder malignancies in the United States, several histopathologic entities exist, including squamous cell carcinoma, adenocarcinoma, melanoma, and neuroendocrine tumors. Furthermore, there are variant histopathologic subtypes of urothelial carcinoma (eg, the plasmacytoid variant), which are often aggressive. Atypical benign bladder masses are diverse and can have inflammatory or iatrogenic causes and mimic malignancy. ^© RSNA, 2022 Online supplemental material is available for this article.

Plasmacytoid Urothelial Carcinoma of the Bladder That Manifests Disseminated Carcinomatosis of the Bone Marrow: A Case Report of Extremely Rapid Progression

Plasmacytoid urothelial carcinoma (PUC) of the bladder is a rare variant of invasive urothelial carcinoma (UC) with aggressive behavior. Despite its prognosis being poorer than that of conventional UC, a median overall survival of approximately 2 years is ensured when it is treated with radical cystectomy (RC), and few patients die within a few months of RC. In this paper, we report the case of a patient with PUC who developed widespread bone metastasis only 6 weeks after RC, which resulted in death within 2 months postoperatively.

Clinically undetected plasmacytoid urothelial carcinoma of the urinary bladder with non-mass-forming metastases in multiple organs: an autopsy case

This case report outlines a clinically undetected urinary bladder plasmacytoid urothelial carcinoma (PUC) with multiple metastases detected at autopsy. An 89-year-old man presented with edema in the lower limbs. Pleural fluid cytology revealed discohesive carcinomatous cells, although imaging studies failed to identify the primary site of tumor. The patient died of respiratory failure. Autopsy disclosed a prostate tumor and diffusely thickened urinary bladder and rectum without distinct tumorous lesions. Histologically, the tumor consisted of acinar-type prostate adenocarcinoma with no signs of metastasis. Additionally, small, plasmacytoid tumor cells were observed in the urinary bladder/rectum as isolated or small clustering fashions. These metastasized to the lungs, intestine, generalized lymph nodes in a non-mass-forming manner. Combined with immunohistochemical studies, these tumor cells were diagnosed PUC derived from the urinary bladder. Both clinicians and pathologists should recognize PUC as an aggressive histological variant, which can represent a rapid systemic progression without mass-forming lesions.

Poorly Cohesive Carcinoma of the Nonampullary Small Intestine: A Distinct Histologic Subtype With Prognostic Significance

Poorly cohesive carcinomas (PCCs) are neoplasms characterized by a dyshesive cell invasion pattern featuring single-cell or cord-like stromal infiltration. Although they have been extensively studied in the stomach and other digestive system organs, limited data regarding nonampullary small bowel poorly cohesive carcinomas (SB-PCCs) are hitherto available. The aims of our study were to analyze the clinicopathologic and immunophenotypical features of SB-PCCs (PCC pattern accounting for >50% of the neoplasm) and to compare them with small bowel adenocarcinomas (SBAs), not otherwise specified (SBAs-NOS) and with cancers with a histologically distinct PCC component accounting for 10% to 50% of the neoplasm (mixed-poorly-cohesive-glandular-SBAs). Fifteen SB-PCCs were identified and compared with 95 SBAs-NOS and 27 mixed-poorly-cohesive-glandular-SBAs. Most SB-PCCs (67%) were composed of <10% of signet-ring cells, and all but 1 SB-PCCs exhibited loss of membranous expression of E-cadherin. Compared with SBAs-NOS, SB-PCCs showed a significantly younger patient age at diagnosis, and a stronger association with Crohn disease, and both SB-PCCs and mixed-poorly-cohesive-glandular-SBAs featured a higher rate of lymphovascular and perineural invasion and a lower percentage of mismatch repair-deficient cases. Importantly, the cancer-specific survival of SB-PCC (hazard ratio: 3.81; 95% confidence interval: 1.90-7.64; P<0.001) and mixed-poorly-cohesive-glandular-SBA (4.12; 2.20-7.71; P<0.001) patients was significantly worse compared with SBAs-NOS cases. This study provides objective evidence to the World Health Organization (WHO) 2019 introduction of SB-PCC as a distinctive subtype of nonampullary SBA, by virtue of its unique clinical and histologic features, and suggests that both SB-PCCs and mixed-poorly-cohesive-glandular-SBAs should be separated from SBAs-NOS.

Colonic Adenocarcinoma with Plasmacytoid Feature: Histopathology and Molecular Characteristics of a Rare Neoplasm with an Unusual Presentation

Colorectal carcinoma with noncohesive tumor cells has been described in tumors with signet ring cells (mucinous adenocarcinoma and signet ring cell adenocarcinoma) and rhabdoid feature (carcinoma with sarcomatoid component). Cases of carcinoma with plasmacytoid morphology are rare in the gastrointestinal tract, and a single case of plasmacytoid colorectal carcinoma has been reported. We report the case of a 37-year-old woman who presented with urinary symptoms, hematuria, and abdominal pain. Imaging studies showed segmental sigmoid wall thickening with pericolic infiltration and focal bladder wall thickening. The cystoscopy with transurethral resection of bladder tumor revealed muscle invasion, dis-cohesive carcinoma with plasmacytoid morphology, which was initially misdiagnosed as the plasmacytoid urothelial carcinoma. Immunohistochemical stains showed the tumor cells to be positive for CDX2, CK20, and SATB2 and negative for p63, GATA3, CK7, and Uroplakin II, indicating the colorectal origin of the tumor. The subsequent colonic wall biopsy showed the same tumor. Molecular studies identified BRAF V600E, SMAD4, and p53 mutations associated with aggressive colorectal adenocarcinoma with mucinous/signet ring cell features. Further whole-exome sequencing and whole transcriptome analysis confirmed the colorectal origin of the tumor. This rare colorectal adenocarcinoma with the plasmacytoid feature may represent the signet ring cell adenocarcinoma lacking extracellular mucin or intracellular vacuole. Diagnosis of this rare histological subtype of colorectal carcinoma is important, particularly in the unusual presentation of this aggressive tumor.

T1 bladder carcinoma with variant histology: pathological features and clinical significance

The aim of the study was to stratify high-grade T1 (HGT1) bladder urothelial carcinoma into risk categories based on the presence of variant histology when compared to conventional urothelial carcinoma. The clinicopathological features of 104 HGT1 cases of urothelial carcinoma of the bladder with variant histology present in 34 (37%) were assessed. The endpoint of the study was disease-free survival and cancer-specific survival. Overall, variant histology was identified as a significant predictor of disease-free survival (P = 0.035). The presence of any specific variant histology (squamous, glandular, micropapillary, nested, microcystic, inverted growth, villous-like, basaloid, and lymphoepithelioma-like) was identified as a significant predictor of disease-free survival (P = 0.008) and cancer-specific survival (P = 0.0001) in HGT1 bladder cancer. Therefore, our results support including micropapillary HGT1 urothelial carcinoma within the aggressive high-risk category, as suggested by some recent clinical guidelines, but also favor nested, glandular, and basaloid to be placed in the high-risk category due to their potential of aggressive, life-threatening behavior and their limited response to bacillus Calmette-Guerin therapy. Conversely, the low-risk category would include urothelial carcinomas with squamous, inverted growth, or microcystic morphology, all with limited life-threatening potential and good response to current therapy. A very low-risk category would finally include patients whose tumors present villous-like or lymphoepithelioma-like morphology. In conclusion, our findings support the value of reporting the variant histology as a feature of variable aggressiveness in HGT1 urothelial carcinoma of the bladder.

Bladder Cancer Sample Handling and Reporting: Pathologist's Point of View

The aim of this narrative review is to provide adequate information on handling and reporting of the bladder cancer samples to improve the closely collaboration between pathologists and urologists. The main (but not exclusive) research tool used was PubMed and 87 references were selected and quoted in the text. We have considered handling of biopsies, transurethral resection (TUR), and cystectomy specimens to summarize the different methods of sampling and the related issues. Moreover, we considered and discussed the main prognostic factors, such as histological tumor type, grade, and stage of bladder cancer, that should be described in the pathological report. In addition, critical issues encountered in the interpretation of histological samples were discussed.

Outcomes of poorly differentiated and plasmacytoid variant bladder urothelial carcinoma

Objectives

The aim of this study is to assess the course and management of poorly differentiated bladder urothelial carcinoma (UC), including plasmacytoid UC (PUC), in our local area. Although bladder cancer is relatively common, PUC is a rare and aggressive subtype with a poor prognosis that is still poorly understood.

Materials and Methods

A retrospective assessment of all poorly differentiated high‐grade UC over the last 15 years (2005–2020) in the Hunter New England area was completed. In total, 37 patients were included, and PUC variant was compared with the remaining poorly differentiated UC.

Results

Of the included cases, eight were PUC, nine squamous variant, two neuroendocrine, and one sarcomatoid. Overall, 23 cases proceeded to cystectomy, 15 had chemotherapy (six neoadjuvant), and 11 had radiation therapy. In the PUC subgroup, three had metastatic disease at diagnosis (37.5%). Of the three PUC patients who underwent cystectomy, all were upstaged. Two PUC cases had adjuvant chemotherapy, and one case had radiation. Within the follow‐up period, the PUC group had a cause‐specific mortality of 50% with a mean survival in these patients of 202 days, compared with 37.9% cause‐specific mortality with survival of 671.55 days (p = 0.23) in all other undifferentiated UC cases; 5‐year cause‐specific mortality with Kaplan–Meier analysis was estimated at 26% compared with 59%, respectively (p = 0.058).

Conclusion

Poorly differentiated UC is demonstrated to have a poor prognosis with a high mortality rate, particularly when PUC is present. Given the rarity of these variants, further studies are necessary to explore the impact of current treatment options.

Non-Muscle Invasive Bladder Cancer with Variant Histology: Biological Features and Clinical Implications

BACKGROUND

The most common bladder cancer (BC) histotype is pure urothelial carcinoma (UC), which may undergo divergent differentiation in some cases. Variant histology (VH) presents along variable morphologies, either single or combined between them or with pure UC. From a clinical standpoint, the vast majority of BC is diagnosed at non-invasive or minimally invasive stages, namely as non-muscle invasive BC (NMIBC). There is a wide range of therapeutic options for patients with NMIBC, according to their clinical and pathological features. However, current risk stratification models do not show optimal effectiveness. Evidence from the literature suggests that VH has peculiar biological features, and may be associated with poorer survival outcomes compared to pure UC.

SUMMARY

In order to describe the biological features and prognostic/predictive role of VH in NMIBC, and to discuss current treatment options, we performed a systematic literature search through multiple databases (PubMed/Medline, Google Scholar) for relevant articles according to the following terms, single and/or in combination: "non-muscle invasive bladder cancer," "variant histology," "micropapillary variant," "glandular differentiation," "squamous differentiation," "nested variant," "plasmacytoid variant," and "sarcomatoid variant." We extracted 99 studies including original articles, reviews, and systematic reviews, and subsequently analyzed data from 16 studies reporting on the outcome of NMIBC with VH. We found that the relative rarity of these forms as well as the heterogeneity in study populations and therapeutic protocols results in conflicting findings overall. Key Messages: The presence of VH should be taken into account when counseling a patient with NMIBC, since it may upgrade the disease to high-risk tumor and thus warrant a more aggressive treatment.

Histologically confirmed distant metastatic urothelial carcinoma from the urinary bladder: a retrospective review of one institution's 20-year experience

Background

Urothelial carcinoma (UC) accounts for roughly 90% of bladder cancer, and has a high propensity for diverse differentiation. Recently, certain histologic variants of UC have been recognized to be associated with unfavorable clinical outcomes. Several UC studies have also suggested that tumor budding is a poor prognostic marker. Distant metastasis of UC after radical cystectomy is not uncommon. However, these metastatic lesions are not routinely confirmed with histology.

Methods

We investigated the histopathologic features of 13 cases of UC with biopsy-proven distant metastases, with a special emphasis on histologic variants and tumor budding.

Results

Lymph nodes (6/13, 46%) were the most common metastatic sites, followed by the lung (4/13, 31%), liver (4/13, 31%), and the adrenal gland (2/13, 15%). The histologic variants including squamous (n = 1), micropapillary (n = 4), and plasmacytoid (n = 1) variants in five cases of UC. Most histologic variants (4/5, 80%) of primary UCs appeared in the metastatic lesions. In contrast, high-grade tumor budding was detected in six cases (46%), including one case of non-muscle invasive UC. Our study demonstrates that histologic variants are not uncommonly detected in distant metastatic UCs. Most histologic variants seen in primary UCs persist in the distant metastatic lesions. In addition, high-grade tumor budding, which occurs frequently in primary tumors, may contribute to the development of distant metastasis.

Conclusions

Therefore, assessing the presence or absence of histologic variants and tumor budding in UCs of the urinary bladder, even in non-muscle invasive UCs, may be useful to predict distant metastasis.

Plasmacytoid variant of urothelial carcinoma of the bladder manifesting as bilateral ureteral and small bowel obstruction

Plasmacytoid urothelial carcinoma (PUC) is a rare variant of bladder cancer characterized by distinct histopathology and advanced stage at diagnosis. Multimodal treatment is usually indicated. We present a case of PUC causing bilateral ureteral obstruction with subsequent renal failure followed shortly by malignant small bowel obstruction, demonstrating the need for a high degree of clinical suspicion in diagnosis of this aggressive subtype. Moreover, the local invasiveness of the disease cannot be understated, given that it can rapidly spread with little radiologic evidence of progression until it is at an advanced stage.

Cyto-histo correlations of plasmacytoid and micropapillary variants of high-grade urothelial carcinoma: do they fit well in The Paris System for reporting urinary cytology?

INTRODUCTION

Plasmacytoid and micropapillary variants of high-grade urothelial carcinoma (HGUC) exhibit unique histologic morphology and very aggressive clinical behavior. However, the morphology of these 2 variants in urinary cytology is not well studied and evaluated using The Paris System for reporting urinary cytology.

MATERIALS AND METHODS

A database search was performed in all patients with the diagnosis of plasmacytoid or micropapillary HGUC. A total of 5 patients with positive urinary cytology cases were identified. The cytomorphology of every urinary cytology case was correlated with the histologic features in the surgical specimens from the same patient.

RESULTS

One urine and 4 bladder washings were evaluated. Cytologically, plasmacytoid HGUCs are characterized by single, large tumor cells with hyperchromasia, irregular nuclear membranes, and vacuolated cytoplasm. The nuclear-to-cytoplasmic (N:C) ratio was less than 0.5 in many of the malignant cells due to the abundant cytoplasm. The cytology features of micropapillary HGUC include the presence of micropapillae of tumor cells with no fibrovascular core. Individual high-grade urothelial cells were also identified in all 4 cases, but 1 (25%) of these had only rare cells meeting The Paris System criteria for HGUC due to abundant cytoplasm and lack of hyperchromasia in most malignant cells.

CONCLUSIONS

Plasmacytoid and micropapillary variants of HGUC have unique cytomorphologic features in urinary cytology specimens, which are reflective of the corresponding histological findings. These 2 clinically aggressive variants of HGUC may not be as readily interpreted as malignant using The Paris System for reporting urinary cytology, creating potential diagnostic pitfalls.