Invasive Urothelial Carcinoma With Chordoid Features: A Report of 12 Distinct Cases Characterized by Prominent Myxoid Stroma and Cordlike Epithelial Architecture

International Society of Urological Pathology (ISUP) Consensus Conference on Current Issues in Bladder Cancer. Working Group 2: Grading of Mixed Grade, Invasive Urothelial Carcinoma Including Histologic Subtypes and Divergent Differentiations, and Non-Urothelial Carcinomas

The 2022 International Society of Urological Pathology (ISUP) Consensus Conference on Urinary Bladder Cancer Working Group 2 was tasked to provide evidence-based proposals on the applications of grading in noninvasive urothelial carcinoma with mixed grades, invasive urothelial carcinoma including subtypes (variants) and divergent differentiations, and in pure non-urothelial carcinomas. Studies suggested that predominantly low-grade noninvasive papillary urothelial carcinoma with focal high-grade component has intermediate outcome between low- and high-grade tumors. However, no consensus was reached on how to define a focal high-grade component. By 2004 WHO grading, the vast majority of lamina propria-invasive (T1) urothelial carcinomas are high-grade, and the rare invasive low-grade tumors show only limited superficial invasion. While by 1973 WHO grading, the vast majority of T1 urothelial carcinomas are G2 and G3 and show significant differences in outcome based on tumor grade. No consensus was reached if T1 tumors should be graded either by the 2004 WHO system or by the 1973 WHO system. Because of the concern for underdiagnosis and underreporting with potential undertreatment, participants unanimously recommended that the presence of urothelial carcinoma subtypes and divergent differentiations should be reported. There was consensus that the extent of these subtypes and divergent differentiations should also be documented in biopsy, transurethral resection, and cystectomy specimens. Any distinct subtype and divergent differentiation should be diagnosed without a threshold cutoff, and each type should be enumerated in tumors with combined morphologies. The participants agreed that all subtypes and divergent differentiations should be considered high-grade according to the 2004 WHO grading system. However, participants strongly acknowledged that subtypes and divergent differentiations should not be considered as a homogenous group in terms of behavior. Thus, future studies should focus on individual subtypes and divergent differentiations rather than lumping these different entities into a single clinicopathological group. Likewise, clinical recommendations should pay attention to the potential heterogeneity of subtypes and divergent differentiations in terms of behavior and response to therapy. There was consensus that invasive pure squamous cell carcinoma and pure adenocarcinoma of the bladder should be graded according to the degree of differentiation. In conclusion, this summary of the International Society of Urological Pathology Working Group 2 proceedings addresses some of the issues on grading beyond its traditional application, including for papillary urothelial carcinomas with mixed grades and with invasive components. Reporting of subtypes and divergent differentiation is also addressed in detail, acknowledging their role in risk stratification. This report could serve as a guide for best practices and may advise future research and proposals on the prognostication of these tumors.

Invasive urothelial carcinoma with chordoid features or abundant myxoid stroma: A reappraisal of morphologic spectrum and risk stratification based on molecular classification

Urothelial carcinoma (UC) with myxoid stroma or chordoid features is a rare diagnosis. We retrospectively collected data from 17 cases of diagnosed UC with myxoid stroma, mucin production, or chordoid features. We aimed to investigate the molecular subtypes of this neoplasm and to assess subtype correlations with clinical outcomes. Immunohistochemical (IHC) staining with a panel composed of markers for basal subtypes (CK5/6, CK14, and CD44) and luminal subtypes (GATA3, FOXA1, and CK20) was performed. Morphologically, all cases included an at least partial conventional UC component, with the first histologic pattern, named as "typical", characterized by a small- or medium-sized tumor cell nest. The second histologic pattern, named as "chordoid", was characterized by tumor cells with cording that mimic extra-skeletal myxoid chondrosarcoma or chordoma, and the third histologic pattern, named as "sarcomatoid", was characterized by non-cohesive spindle tumor cells with a mucin-producing or myxoid stroma background. The "typical" cases showed [CK5/6- CK14- CD44-] [GATA3 + FOXA1 + CK20-] IHC results and was classified as lumina subtype. The "chordoid" cases showed [CK5/6 + CK14 + CD44-] [GATA3- FOXA1- CK20-] IHC results and was classified as basal subtype, and the "sarcomatoid" cases showed [CK5/6- CK14- CD44+] [GATA3- FOXA1- CK20-] IHC results and was "not classified". All pT3 cases and all cases with lymph node (LN) metastasis belonged to the "sarcomatoid" pattern. All patients who had metastasis or died showed the "chordoid" or "sarcomatoid" morphology. Our findings suggest that UC with myxoid stroma/chordoid features shows characteristic expression of luminal and basal markers and different prognosis according to the morphologic pattern spectrum.

Urothelial carcinoma of the bladder with abundant myxoid stroma: A case report and literature review

INTRODUCTION

Abundant myxoid stroma rarely occurs in urothelial carcinomas (UCs). We report an 83-year-old woman with UC of the urinary bladder with abundant myxoid stroma. We summarized the clinicopathological features, immunophenotype, diagnosis, and differential diagnosis of this type of bladder cancer, in order to improve the understanding of surgeons and pathologists.

PATIENT CONCERNS

An 83-year-old female presented with hematuria and frequent micturition, without odynuria, hypogastralgia, or fever.

DIAGNOSIS

The computed tomography scan demonstrated extensive tumors in the anterior wall of the bladder and a soft tissue shadow anterior to the sacrum. Cystoscopy showed massive wide-based tumors located on the anterior and lateral walls of the bladder, with no tumor involving the bladder neck. Multiple punch biopsies were performed, the histologic evaluation of which revealed a poorly differentiated invasive UCs with myxoid stroma.

INTERVENTIONS

The patient underwent a laparoscopic radical cystectomy and cutaneous ureterostomy.

OUTCOMES

The patient discharged without any complications. Histologic evaluation revealed an invasive UC; the most prominent feature was an abundant myxoid stroma that covered approximately 80% of the lesion and the tumor cells were arranged in cords, small nests, or a sheet-like structure. Immunohistochemically, the tumor cells were positive for CK19, CK20, VEGF, EGFR, p63, 34βE12, MUC1, GATA3, uroplakin3, and TopII (rate = 15%), while the Ki-67 proliferation index was 10%. The myxoid stroma in the mesenchyme stained positively with AB-PAS and colloidal iron, and some tumor cells stained positive for colloidal iron. Considering the histologic, histochemical, and immunohistochemical findings, a diagnosis of UC with abundant myxoid stroma was made. After surgery, the regular follow-up was continued in clinic, and there was no recurrence for 2 years.

CONCLUSION

Morbidity associated with UC with abundant myxoid stroma is very low. The diagnosis mainly depends on histopathological and immunohistochemical findings.

Yolk sac tumor differentiation in urothelial carcinoma of the urinary bladder: a case report and differential diagnosis

Background

Yolk sac tumor (YST) is a germ cell neoplasm that arises predominantly in the gonads, but can also derive from somatic neoplasms in extragonadal locations. These latter cases have been documented in several organs, although reports from the urinary tract are limited. To our knowledge, this is the first report of a bladder urothelial carcinoma with a predominant component of YST differentiation.

Case presentation

We present a unique case of a 76-year-old man with a recurrent urinary bladder tumor, initially interpreted as a high grade urothelial carcinoma with glandular differentiation. In the recurrent tumor, diverse histological patterns were identified, including glandular, hepatoid and sarcomatoid. This tumor showed positivity for AFP, GLP3 and SALL4, and negativity for CK7 and EMA. Fluorescent in situ hybridization study showed a polysomic pattern of chromosome 12. All these findings led to the final diagnosis of a YST derived from urothelial carcinoma.

Conclusions

YST differentiation should be considered in the differential diagnosis of a high grade urothelial carcinoma, particularly when glandular and other unusual patterns are observed.

A Fibromyxoid Stromal Response is Associated with Muscle Invasion in Canine Urothelial Carcinoma

Canine urothelial carcinoma (UC) is the most common type of cancer of the lower urinary tract and tends to affect elderly neutered female dogs, with a high predisposition for Scottish terriers. Tumour stroma, inflammation and necrosis are poorly characterized in canine UC and their role as prognostic factors is unknown. The aims of this study were to (1) assess histologically 381 canine UCs, with emphasis on myxoid tumour stroma, inflammation and necrosis and (2) assess possible associations between these features and the available epidemiological data as well as bladder wall muscle invasion. In 103 of 381 (27%) cases, the stroma was mixed collagenous and myxoid (fibromyxoid), which was strongly associated with invasive growth of muscle (P <0.0001). Peritumoural and intratumoural inflammation was present in 308 of 345 (89%) and 287 of 381 (75%) cases, respectively, and was mostly mild and lymphoplasmacytic. One hundred and fifteen of the 381 (30%) cases showed a variable eosinophilic inflammation and 58 of 381 (15%) presented with formations of one or several lymphoid follicles. Twenty-four percent (91 of 381) of cases had tumour necrosis, which was typically mild. In 83 of 91 (91%) cases, the necrosis was comedo-like. Moderate to severe tumour necrosis was associated with the presence of moderate to predominant fibromyxoid tumour stroma (P <0.02). The results of this study indicate that fibromyxoid stroma is common in canine UC and is a strong indicator for invasive growth of muscle, which is consistent with a poor prognosis. Based on histomorphology, tumour necrosis in canine UC is best described as comedonecrosis.

Morphologic and Molecular Characteristics of Bladder Cancer

Bladder cancer is the fourth most common cancer in men, and is associated with significant morbidity and mortality. Pathologic evaluation of urothelial cancers relies predominantly on histomorphologic features but can be aided in a small subset of cases by immunohistochemical analyses. Distinction of papillary versus flat lesions, low-grade versus high-grade cytology, and histologic variants and the presence or absence of invasive tumor is important for proper clinical management. Advances in the molecular alterations associated with the various subtypes of urothelial carcinoma have been made but such studies are ongoing.

Sarcomatoid Urothelial Carcinoma of the Bladder: Analysis of 28 Cases With Emphasis on Clinicopathologic Features and Markers of Epithelial-to-Mesenchymal Transition

Context.—Sarcomatoid urothelial carcinoma (UCa) is a rare but aggressive variant of bladder cancer that can show diagnostic challenges even using ancillary techniques.

Objective.—To examine immunohistochemical markers in the context of sarcomatoid UCa, including those associated with epithelial-to-mesenchymal transition.

Design.—Twenty-eight cases of sarcomatoid UCa were rereviewed. Clinical outcomes were obtained through database search. Immunohistochemistry for clinical and epithelial-to-mesenchymal transition markers was performed.

Results.—All patients had biopsy-proven invasive UCa; 61% (17 of 28) had sarcomatoid UCa at initial diagnosis. A recognizable epithelial component(s) was present in 17 lesions. The sarcomatoid component accounted for 65% of the lesion (average), with heterologous elements present in 3 of 28 cases (11%). The morphologic spectrum of the sarcomatoid element included spindled not otherwise specified, myxoid, pseudoangiosarcomatous, and malignant fibrous histiocytoma–like undifferentiated features. The sarcomatoid component was immunoreactive for pancytokeratin (22 of 26; 85%), p63 (20 of 26; 77%), cytokeratin 903 (17 of 26; 65%), cytokeratin 7 (16 of 26; 62%), GATA3 (16 of 26; 62%), and cytokeratin 5/6 (16 of 26; 62%). STAT-6, CD31, CD34, and HMB45 were all nonreactive, whereas smooth muscle actin often showed at least focal immunoreactivity (22 of 26; 85%). Epithelial-to-mesenchymal transition markers were frequently expressed, including vimentin (26 of 26; 100%), FoxC2 (26 of 26; 100%), SNAIL (23 of 26; 88.5%), and ZEB1 (18 of 26; 69.2%). Follow-up was available for 24 patients (median, 7 months). Sixteen of 28 patients (57%) died of disease (overall mean survival, 9.1 months). The presence of myxoid or chordoid features was associated with reduced survival (P &lt; .05).

Conclusions.—Sarcomatoid UCa is an aggressive form of UCa that frequently expresses epithelial-to-mesenchymal transition markers, suggesting a possible mechanism associated with aggressive tumor behavior.

Update for the practicing pathologist: The International Consultation On Urologic Disease-European association of urology consultation on bladder cancer

The International Consultations on Urological Diseases are international consensus meetings, supported by the World Health Organization and the Union Internationale Contre le Cancer, which have occurred since 1981. Each consultation has the goal of convening experts to review data and provide evidence-based recommendations to improve practice. In 2012, the selected subject was bladder cancer, a disease which remains a major public health problem with little improvement in many years. The proceedings of the 2nd International Consultation on Bladder Cancer, which included a 'Pathology of Bladder Cancer Work Group,' have recently been published; herein, we provide a summary of developments and consensus relevant to the practicing pathologist. Although the published proceedings have tackled a comprehensive set of issues regarding the pathology of bladder cancer, this update summarizes the recommendations regarding selected issues for the practicing pathologist. These include guidelines for classification and grading of urothelial neoplasia, with particular emphasis on the approach to inverted lesions, the handling of incipient papillary lesions frequently seen during surveillance of bladder cancer patients, descriptions of newer variants, and terminology for urine cytology reporting.

Mucinous urothelial carcinoma of the renal pelvis

Urothelial carcinoma with abundant myxoid stroma is a newly-described and extremely rare entity. Since only very few cases have been reported, there is no consensus on its nomenclature. Microscopic examination revealed invasive urothelial carcinoma with widespread low-grade noninvasive areas. There were focal invasive areas in the neighborhood of the renal parenchyma. Malignant urothelial tumor/cell groups localized in the stroma had abundant myxoid/mucinous background in the invasive areas. The cytoplasm of the tumoral cells was more eosinophilic in these areas and the cells formed small groups and cords. Histochemically, PAS and Alcian Blue were positive in the cytoplasm of the tumoral cells and in the stroma while negative in the non-mucinous areas. Immunohistochemically, the tumoral cells of the mucinous invasive areas diffusely expressed MUC1 and MUC2. We discuss the origin of the mucinous/myxoid stroma, the tumor’s nature and its nomenclature with histochemical and immunohistochemical features.

A synchronous occurrence of urothelial carcinoma with abundant myxoid stroma and inverted papilloma of the urinary bladder

Abundant myxoid stroma rarely occurs in urothelial carcinomas, and may cause diagnostic challenges when cells with eosinophilic cytoplasm forming nests and cords in a myxoid background are seen, particularly in the absence of typical carcinomatous appearance. Microscopic examination of transurethral resection specimen of a 71-year-old male patient revealed non-cohesive oval or elongated tumor cells with eosinophilic cytoplasm arranged in cord-like filigree pattern in an abundant myxoid stroma. Immunohistochemically the tumor was positive for cytokeratin 7, cytokeratin 20, and 34BE12. About 90 to 100% nuclear staining was observed with p63, p53, and Ki-67. A second neoplasm with a flat overlying urothelial epithelium and a complete inverted cellular growth pattern was also noted. The neoplasm exhibited less than 2% and 10% nuclear staining with Ki-67 and p53, respectively. Considering histological, histochemical, and immunohistochemical findings, a diagnosis of synchronous urothelial carcinoma with abundant myxoid stroma and inverted papilloma was made.

Ovarian clear cell carcinoma with choriocarcinomatous differentiation: report of a rare and aggressive tumor

Ovarian epithelial tumors of nongerm cell origin with true choriocarcinomatous differentiation are rare. To date, there are only 5 documented cases in the literature. In the reported cases, the epithelial component was of mixed cell types or of mucinous differentiation. To the best of our knowledge, an ovarian carcinoma exclusively of clear cell differentiation coexisting with a pure choriocarcinoma has not been reported earlier. A 48-year-old postmenopausal woman was found to have a large pelvic mass with lung and liver metastases. Trucut biopsy of the mass showed a poorly differentiated carcinoma that was immunoreactive for CK7 and hCG. She received 6 cycles of neoadjuvant chemotherapy that included 3 cycles of etoposide/cisplatin and 3 cycles of paclitaxel/etoposide-paclitaxel/carboplatin (TE/TP) with partial response. Debulking surgery was carried out subsequently. Pathologic examination showed an ovarian clear cell carcinoma with a second component of choriocarcinoma in which the bilaminar growth pattern of cytotrophoblast and syncytiotrophoblasts was striking. Despite additional therapy, which included 2 cycles of TE/TP and 2 cycles of gemcitabine/taxotere, the disease progressed and the patient died 11 months postoperatively. This report showed that ovarian clear cell carcinoma with choriocarcinomatous differentiation is a highly aggressive tumor and has a very poor prognosis. Nonetheless, there may be a role for neoadjuvant chemotherapy that targets both the clear cell and the choriocarcinoma components to reduce the volume of the disease before debulking surgery.

Papillary Urothelial Carcinoma of the Bladder With Exuberant Pseudosarcomatous Stromal Reaction Following Radiation Therapy

An 82-year-old man, with 6-year history of radical prostatectomy followed by radiotherapy performed for prostatic carcinoma, underwent transurethral resection of a papillary tumor of the bladder lateral walls. Histologically, the lesion displays 2 distinct components: epithelial and stromal. The epithelial component was composed of a noninvasive papillary urothelial carcinoma, predominantly low grade and focally high grade. The stromal component exhibited extensive myxoid changes with increased cellularity but lacking cellular atypia and mitoses. The epithelial component was immunoreactive for pan-cytokeratins and negative for smooth muscle actin (SMA) and vimentin. The stromal component exhibited focal positivity for pan-cytokeratins and SMA, and diffuse immunoreactivity for vimentin. The ki67 reached 70% in the epithelial component and 20% in the stromal component. Papillary intraurothelial carcinoma following radiotherapy may be associated with pseudosarcomatous stromal proliferation. The clinical history and the lack of cellular atypia and mitoses point toward the correct diagnosis.