Molecular Genetic Features of Primary Nonurachal Enteric-type Adenocarcinoma, Urachal Adenocarcinoma, Mucinous Adenocarcinoma, and Intestinal Metaplasia/Adenoma: Review of the Literature and Next-generation Sequencing Study

Primary urethral adenocarcinoma harbors recurrent KRAS and EGFR alterations

Primary urethral adenocarcinoma is an extremely rare malignancy with an unclear pathogenesis. Previously, we reported 4 brachytherapy-associated (BA) urethral mucinous adenocarcinomas that developed following treatment for prostate cancer. In the present study, we report one additional BA and 3 radiation-independent (RI) urethral adenocarcinomas. The aim of this study is to explore the molecular alterations and to compare the clinicopathologic features. RNA sequencing was performed on 5 tumors, and a next-generation sequencing (NGS)-based fusion assay was used to identify gene fusions in 6 tumors. Additionally, NGS-based targeted genomic DNA sequencing was employed to analyze one metastatic BA tumor and one metastatic RI tumor. The 8 patients had a mean age of 67 (range: 37-87) years, with one being female in the RI cohort. Cystoscopy revealed the following urethral findings: a papillary lesion (4/7), mass causing obstruction (1/7) and irregular friable tissue (2/7). Seven patients underwent urethrectomy with cystectomy/prostatectomy/hysterectomy. The mean tumor size was 3.4 cm (range: 1.5-6.5). Adenocarcinoma in situ was noted in 5 tumors. All 5 BA tumors originated from the prostatic urethra, with 4 showing mucinous morphology and one enteric morphology, and showed moderate to poor differentiation and tumor stages of pT2 (2/4), pT3 (1/3) and pT4 (1/4). Two patients developed metastasis, one at 3.3 and one at 4.2 years after diagnosis, and all patients were alive at a median follow-up of 4.5 (range: 2-14) years. In contrast, 3 RI tumors arose from bulbar, prostatic, or female mid/distal urethra, presenting as enteric, mucinous, and not otherwise specified (NOS) subtypes, with well to moderate differentiation and a tumor stage of pT4 (2/2). Two died of the disease, while one was alive without disease at a median follow-up of 4 (range: 2.2-14.5) years. All tumors were diffusely positive for CK20, CDX2 (7/7), and AMACR (3/3), and lacked nuclear β-catenin expression (5/5). Most expressed CK7 (5/7). KRAS mutations (p.Gly12Val and p.Gly13Asp) were observed in one BA mucinous tumor and one RI NOS tumor with the p.Gly13Asp mutation also detected in the metastatic RI tumor. The EGFR p.Ser784Phe mutation was detected in one RI enteric tumor. TP53 p.Val172Phe, CDKN2A p.Leu32_Leu37del, and amplifications of EGFR and MDM2, were identified in a metastatic BA enteric tumor. No fusion transcripts were identified. In conclusion, urethral adenocarcinoma harbors recurrent KRAS and EGFR alterations, independent of prior radiotherapy. RI tumors appear to be associated with a worse prognosis compared to BA tumors.

Primary adenocarcinoma of the urinary tract and its precursors: Diagnostic criteria and classification

Primary adenocarcinoma of the urinary bladder is a rare malignancy, comprising up to 2% of bladder cancers, predominantly in males. Its rarity and similarity to urothelial carcinoma and secondary adenocarcinomas pose diagnostic challenges. A comprehensive literature review was conducted on the diagnosis, classification, morphological and immunophenotypic characteristics, and molecular profiles of primary adenocarcinoma, urachal adenocarcinoma, and precursor lesions. Primary adenocarcinoma exhibits diverse morphological patterns, including enteric, mucinous, signet ring cell, and mixed types. Immunohistochemistry is useful in differentiating primary adenocarcinoma from metastatic adenocarcinomas and secondary involvement. Genetic studies reveal mutations common in colorectal and bladder adenocarcinomas (KRAS, TP53, PIK3CA) and novel primary adenocarcinoma-specific mutations (OR2L5). Urachal adenocarcinoma shares morphological features with primary adenocarcinoma but typically occurs in younger patients with unique genomic and distinct immunoprofile. Potential precursor lesions include villous adenoma, cystitis glandularis, and intestinal metaplasia, and warrant close clinical follow-up. Despite advances in histopathological and molecular diagnostics, primary adenocarcinoma remains challenging to diagnose due to its rarity and morphological heterogeneity. Ongoing research into its molecular characteristics is essential to refine diagnostic criteria and therapeutic approaches. Thorough clinical and pathological assessment is crucial for accurate diagnosis, classification, and clinical management.

Mucinous Borderline Tumors of the Pelvicalyceal System: Report of Two Tumors With Molecular Findings and Review of Literature

Mucinous borderline tumors of the pelvicalyceal system are exceedingly rare tumors with very little information regarding their clinicopathological characteristics and molecular underpinnings in the published literature. Herein, we report two mucinous borderline tumors and review the literature pertaining to these tumors. The patients were women who presented with flank pain without any history of nephrolithiasis. Abdominal computed tomography (CT) showed multiloculated cystic lesions without mural nodules involving the kidney (Bosniak category III). The nephrectomy specimens showed multiloculated cysts filled with mucoid material, without any solid areas. On microscopic examination, the cystic spaces were lined predominantly by a single layer of mucinous epithelium with variable foci of epithelial stratification. Extensive sampling of the tumors did not show any evidence of invasion. The tumor cells were positive for keratin 7, keratin 20, and CDX2 and were negative for urothelial markers. Molecular analysis performed on one of the tumors showed loss of function mutation of SMAD4 p.S32fs. The presence of SMAD4 alterations alludes to the potential role of the SMAD4-TGFß pathway in the pathogenesis of this tumor. On clinical follow-up, both patients are well with no evidence of disease. Our case report expands on the clinical characteristics of these rare tumors and provides insight into the previously unreported molecular landscape of this tumor.

Glandular Lesions of the Urinary Bladder: Diagnostic and Molecular Updates

Glandular lesions in the urinary tract or their associated pathologies can pose a diagnostic challenge. There is a variety of benign alterations and tumor types that need to be taken into account in differential diagnostic considerations. In recent times, efforts for better defining these alterations or lesions both on the histopathological and molecular levels have been undertaken. This article will provide an update on current diagnostic and molecular considerations of these lesions.

Mutational signature and prognosis in adenocarcinoma of the bladder

Adenocarcinoma of the bladder is a rare urinary bladder carcinoma with limited therapy options due to lack of molecular characterization. Here, we aimed to reveal the mutational and transcriptomic landscapes of adenocarcinoma of the bladder and assess any relationship with prognosis. Between February 2015 and June 2021, a total of 23 patients with adenocarcinoma of the bladder were enrolled. These included 16 patients with primary bladder adenocarcinomas and seven patients with urachal adenocarcinoma. Whole exome sequencing (16 patients), whole genome sequencing (16 patients), bulk RNA sequencing (RNA-seq) (19 patients), and single-cell RNA-seq (5 patients) were conducted for the specimens. Correlation analysis, survival analysis, and t-tests were also performed. Prevalent T>A substitutions were observed among somatic mutations, and major trinucleotide contexts included 5'-CTC-3' and 5'-CTG-3'. This pattern was mainly contributed by COSMIC signature 22 related to chemical carcinogen exposure (probably aristolochic acid), which has not been reported in bladder adenocarcinoma. Moreover, genes with copy number changes were also enriched in the KEGG term 'chemical carcinogenesis'. Transcriptomic analysis suggested high immune cell infiltration and luminal-like features in the majority of samples. Interestingly, a small fraction of samples with an APOBEC-derived mutational signature exhibited a higher risk of disease progression compared with samples with only a chemical carcinogen-related signature, confirming the molecular and prognostic heterogeneity of bladder adenocarcinoma. This study presents mutational and transcriptomic landscapes of bladder adenocarcinoma, and indicates that a chemical carcinogen-related mutational signature may be related to a better prognosis compared with an APOBEC signature in adenocarcinoma of the bladder. © 2024 The Pathological Society of Great Britain and Ireland.

Precursors of urinary bladder cancer: molecular alterations and biomarkers

Clinical surveillance and follow-up of patients diagnosed with or at risk for urinary bladder cancers represent long-term, invasive, and costly processes for which supplemental biomarker information could help provide objective, personalized risk assessment. In particular, there are several precursors and possible precursors to urinary bladder cancer for which clinical behavior is heterogenous and interobserver variability in histopathologic diagnosis make it difficult to standardize management. This review seeks to highlight these precursor lesions from a diagnostic perspective (including flat urothelial lesions, papillary urothelial lesions, squamous lesions, and glandular lesions) and qualify known multiomic biomarkers that may help explain their behavior, predict patient risk, and acknowledge the nuance inherent to the question of whether these lesions are "benign" or "preneoplastic."

Clinical sequencing identifies potential actionable alterations in a high rate of urachal and primary bladder adenocarcinomas

OBJECTIVE

Administration of targeted therapies provides a promising treatment strategy for urachal adenocarcinoma (UrC) or primary bladder adenocarcinoma (PBAC); however, the selection of appropriate drugs remains difficult. Here, we aimed to establish a routine compatible methodological pipeline for the identification of the most important therapeutic targets and potentially effective drugs for UrC and PBAC.

METHODS

Next-generation sequencing, using a 161 cancer driver gene panel, was performed on 41 UrC and 13 PBAC samples. Clinically relevant alterations were filtered, and therapeutic interpretation was performed by in silico evaluation of drug-gene interactions.

RESULTS

After data processing, 45/54 samples passed the quality control. Sequencing analysis revealed 191 pathogenic mutations in 68 genes. The most frequent gain-of-function mutations in UrC were found in KRAS (33%), and MYC (15%), while in PBAC KRAS (25%), MYC (25%), FLT3 (17%) and TERT (17%) were recurrently affected. The most frequently affected pathways were the cell cycle regulation, and the DNA damage control pathway. Actionable mutations with at least one available approved drug were identified in 31/33 (94%) UrC and 8/12 (67%) PBAC patients.

CONCLUSIONS

In this study, we developed a data-processing pipeline for the detection and therapeutic interpretation of genetic alterations in two rare cancers. Our analyses revealed actionable mutations in a high rate of cases, suggesting that this approach is a potentially feasible strategy for both UrC and PBAC treatments.

Update on Flat and Papillary Urothelial Lesions: Genitourinary Pathology Society Consensus Recommendations

The reporting recommendations on "flat and papillary urothelial neoplasia," published in 2 position articles by the Genitourinary Pathology Society in July 2021, was a collective contribution of 38 multidisciplinary experts aiming to clarify nomenclature, classification of flat and papillary urothelial neoplasia and controversial issues. In this review, we discuss some of these recommendations including nomenclature, practical approaches, and their importance for clinical practice.

An Unusual Location for a Nonurachal Bladder Adenocarcinoma

Malignant bladder neoplasms represent a significant disease burden not only for urologists but also the broader medical community. While the majority of bladder tumors are urothelial in origin, up to two percent are found to be adenocarcinomas. Among bladder adenocarcinomas, roughly one-tenth are urachal and are frequently located at the dome of the bladder where urachal remnants can often be found. We describe a case of bladder adenocarcinoma that presented at the dome of the bladder but ultimately exhibited a nonurachal histology. A 65-year-old male with a history of myocardial infarction and cerebrovascular accident with residual right-sided hemiparesis and aphasia was referred to our clinic for evaluation of a bladder mass discovered in the setting of painless gross hematuria. Diagnostic cystoscopy demonstrated a large mass at the dome of the bladder, and subsequent transurethral resection revealed stage T1 mucinous adenocarcinoma arising in a villous adenomatous lesion without the presence of muscle in the specimen. The patient underwent a robotic-assisted laparoscopic partial cystectomy with extended bilateral pelvic lymph node dissection. Postoperatively, the patient experienced short-lived paralytic ileus and was discharged on postoperative day 5. Follow-up surveillance imaging at 6 months with CT chest, abdomen, and pelvis, repeat office cystoscopy, and negative tumor markers postoperatively indicated no evidence of disease recurrence. Characterization of bladder adenocarcinomas into urachal and nonurachal subtypes is critical in differentiating the operative management and oncologic outcomes of the respective neoplasms. However, given the paucity of literature describing treatment approaches to bladder adenocarcinoma in general, existing methods have largely mirrored genetically similar neoplasms, including ovarian and colon adenocarcinomas. Although there is still much to be understood regarding the potential mechanisms of carcinogenesis of nonurachal adenocarcinomas, further investigation may pave the way for a more standardized treatment paradigm and provide insight into the potential utility of modern immunotherapies.

Multifocal Urinary Tract Metastasis of Colorectal Carcinoma

INTRODUCTION

Secondary urinary tract tumors are uncommon findings and mainly evolve by direct invasion from adjacent organs. Actual metastatic involvement often develops in the urinary bladder, while the upper urinary tract is infrequently affected. In addition, the lungs, breast, and prostate gland are the usual primary sites. Colorectal carcinoma (CRC) may spread to the ureter directly or seeds via vascular or lymphatic channels. It may pose struggles in the differential diagnosis because CRC shares standard pathologic features with the primary adenocarcinoma of the urinary tract.

CASE PRESENTATION

We describe the case of an 81-year-old man who was referred to our hospital with a distal ureteral tumor that was treated by a ureteronephrectomy. The histopathological and genetic analysis established the diagnosis of metastatic CRC along with 3 metastases in the renal pelvis.

CONCLUSION

This rare case highlights the limitations of conventional histological processing, including immunohistochemistry, and it underlines the role of molecular investigations in certain circumstances.

The Genitourinary Pathology Society Update on Classification and Grading of Flat and Papillary Urothelial Neoplasia With New Reporting Recommendations and Approach to Lesions With Mixed and Early Patterns of Neoplasia

The Genitourinary Pathology Society (GUPS) undertook a critical review of the recent advances in bladder neoplasia with a focus on issues relevant to the practicing surgical pathologist for the understanding and effective reporting of bladder cancer, emphasizing particularly on the newly accumulated evidence post-2016 World Health Organization (WHO) classification. The work is presented in 2 manuscripts. Here, in the first, we revisit the nomenclature and classification system used for grading flat and papillary urothelial lesions centering on clinical relevance, and on dilemmas related to application in routine reporting. As patients of noninvasive bladder cancer frequently undergo cystoscopy and biopsy in their typically prolonged clinical course and for surveillance of disease, we discuss morphologies presented in these scenarios which may not have readily applicable diagnostic terms in the WHO classification. The topic of inverted patterns in urothelial neoplasia, particularly when prominent or exclusive, and beyond inverted papilloma has not been addressed formally in the WHO classification. Herein we provide a through review and suggest guidelines for when and how to report such lesions. In promulgating these GUPS recommendations, we aim to provide clarity on the clinical application of these not so uncommon diagnostically challenging situations encountered in routine practice, while also importantly advocating consistent terminology which would inform future work.