The association between variant histology and prognostic, histomorphological and clinical aspects of bladder urothelial carcinoma

This study underscores the imperative consideration of histological subtypes and divergent differentiation in accurately estimating bladder urothelial carcinoma prognosis and guiding treatment decisions. A comparative analysis was conducted, examining clinical, histological, and prognostic factors between conventional urothelial carcinoma and urothelial carcinoma with variant histology in a clinical sample. A retrospective analysis of slides and other clinicopathologic data was conducted these cases, with an emphasis on key diagnostic elements. We examined 829 cases of urothelial carcinoma of the bladder, comprising of 744 transurethral resection (TUR) and 85 radical cystectomy (RS) specimens, an analysis that showed that 80.5 % (667 cases) were conventional urothelial carcinoma (CUC) and that 19.5 % (162 cases) exhibited variant histology (hereafter “urothelial carcinoma with subtype histology” [UCSH]). TNM classifications for the RS cases were as follows: 2 cases were stage group 0a, 11 stage group 1, 16 stage group 2, 45 stage group 3a, 2 stage group 3b, 1 stage group 4a, and 8 stage group 4b. Only 2 of the RS cases were found to be non-invasive. Among 744 TUR specimens, 387 were found to have a non-invasive tumor whereas 357 had invasive tumors. The most prevalent subtype in the UCSH group was urothelial carcinoma with squamous differentiation, accounting for 54.3 % (88 cases). Notably, 8.02 % (13 cases) exhibited more than one histological subtype. Papillary configuration, histological grade, lamina propria, muscularis mucosa and serosa invasion, lymphovascular invasion, presence of urothelial carcinoma in situ, and overall survival significantly differed between the UCSH and CUC groups (p < 0.05). However, mean age, gender, tumor size, lymphocytic response, disease-free survival, and survival status did not differ significantly (p > 0.05). Among the UCSH group, lower levels of papillary configuration, higher histological grade, higher degree of lamina propria, muscularis mucosa and serosa invasion, and the presence of carcinoma in situ corresponded to higher percentage of histological subtype morphology (p < 0.05). No significant difference in survival status was observed between the groups with and without subtype histology (p = 0.083). This study found that clinical and histopathological prognostic factors associated with a more aggressive disease were linked to the presence and percentage of histological subtypes. Recognizing histological subtype is crucial for treatment decisions and prognosis prediction in urothelial carcinoma cases with these subtypes.