Invasive high-grade urothelial carcinoma of the bladder, renal pelvis, ureter, and prostatic urethra arising in a background of urothelial carcinoma with an inverted growth pattern: a contemporary clinicopathological analysis of 91 cases

Clinicopathologic Features of Noninvasive Inverted Urothelial Papillary Tumor

OBJECTIVES

Clinicopathologic features and recurrence rates of inverted noninvasive urothelial papillary tumors have been poorly characterized to date with few larger studies evaluating long-term outcomes. The spectrum of histomorphology, clinical features, and prognosis of inverted lesions of the urinary bladder are retrospectively reviewed.

METHODS

Archived paraffin-embedded urothelial tumor samples from patients diagnosed with inverted urothelial papillary lesions between January 2005 and June 2020 were collated. A matched control population of patients with exophytic papillary lesions of the urothelium diagnosed during the same time period was randomly selected. The conventional clinicopathologic features of inverted urothelial papillary tumor were evaluated retrospectively and patient demographics, tumor characteristics, recurrence, and survival information were recorded.

RESULTS

Lower recurrence rates were observed for inverted papillary urothelial neoplasm of low malignant potential (IPUNLMP) relative to papillary urothelial neoplasms of low malignant potential and for low-grade papillary urothelial carcinoma with an inverted growth pattern (LG-PUCI) relative to low-grade papillary urothelial carcinomas. No recurrence was found among the inverted urothelial papilloma cases. The 2- and 5-year disease-free survival rates were 100.0% and 85.2% for IPUNLMP patients; 94.4% and 80.4% for papillary urothelial neoplasms of low malignant potential; 89.5% and 82.0% for LG-PUCI; 73.7% and 54.6% for low-grade papillary urothelial carcinoma; 40.0% and 20.0% for high-grade papillary urothelial carcinoma with an inverted growth pattern patients and 26.7% and 26.7% for high-grade papillary urothelial carcinoma. Multivariate Cox regression analysis of IPUNLMP and LG-PUCI/high-grade papillary urothelial carcinoma with an inverted growth pattern indicated that tumor number (hazard ratio=4.356; 95% CI: 1.145-16.570; P =0.031) was a powerful prognostic factor for disease-free survival.

CONCLUSION

Noninvasive, papillary urothelial lesions of the bladder tend to have lower recurrence and a better outcome if an inverted growth pattern is shown.

Primary urothelial carcinoma of the ureter without concurrent renal pelvic or bladder carcinoma: A contemporary clinicopathologic analysis

Primary urothelial carcinoma (UCa) of the ureter is relatively uncommon, comprising less than 10% of all urinary tract tumors. Typically, ureteral UCa is found in association with other urinary tract tumors, such as renal pelvic or bladder UCa, making it challenging to analyze the clinicopathologic features in isolation. With only a few small case series and case reports available, our understanding of primary ureteral UCa is limited. Herein, we conducted one of the largest studies to date of primary ureteral UCa without concurrent renal pelvic or bladder UCa. Clinicopathologic parameters including extent of invasion, lymphovascular invasion, variant histology, presence of UCa in situ, inverted growth pattern, and clinical follow-up information were obtained. Ninety-seven cases were included in the study. Thirty-nine cases (40%) showed invasion, the preponderance of which invaded lamina propria (15%; 15/97), followed by periureteral soft tissue/adipose (14%; 14/97), muscularis propria (9%; 9/39), and seminal vesicle invasion (1%; 1/97). Clinical follow-up data was available for 80/89 (89%) patients with a mean duration of 35 months (range: 1-206 months). Metastatic UCa developed in 28/89 (35%) patients, 20/28 (71%) of which had invasive disease at presentation. Of the 17 (21%) patients who died, 12 (71%) initially presented with invasive UCa. Although more patients had non-invasive UCa, the propensity for worse outcomes in patients with invasive disease is greater compared to other urinary tract sites. These findings further emphasize the importance of early recognition of these tumors, in view of the relatively high preponderance of advanced disease and mortality in a subset of these patients.

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.

Distinctive morphological and molecular features of urothelial carcinoma with an inverted growth pattern

Urothelial carcinoma with an inverted growth pattern (UC-IGP) is a peculiar entity within the spectrum of urothelial lesions. While efforts have been made over the last few decades to unravel its carcinogenesis and relationship with conventional urothelial carcinoma, the exact classification of inverted urothelial lesions is a matter of debate. The morphological features of UC-IGP pose several issues in differential diagnosis with other mostly benign lesions. Various techniques, including immunohistochemistry, UroVysion, and many molecular methods, have been employed to study the exact nature of this lesion. The aim of this review is to provide a comprehensive overview of the morphological and immunophenotypical aspects of UC-IGP. Moreover, we present and discuss the immunohistochemical and molecular markers involved in diagnosis and prognosis of UC-IGP lesions.