High-Grade Urothelial Carcinoma with Clear-Cell (Glycogen-Rich) Features and Divergent Trophoblastic Differentiation: A Histopathological Case Report

<b>Background and Clinical Significance</b>: Urothelial carcinoma is one of the most commonly diagnosed malignant diseases. However, it has a much more favorable prognosis than other significantly less common malignancies. This statement, however, is true only for conventional urothelial carcinomas, not for those with divergent differentiation or a special type of urothelial carcinoma. <b>Case Presentation</b>: Herein, we present a case report of an 80-year-old female patient with multiple predominantly cardiovascular comorbidities and vascular dementia, who presented to our institution with genital bleeding. Clinical and diagnostic tests were difficult due to patient noncooperation; however, abdominal computer tomography and cystoscopy showed an advanced tumor originating from the ventral bladder wall. Histology of the tumor showed an invasive urothelial malignancy with foci of clear-cell (glycogen-rich) variant and dispersed, pleomorphic cells, which were immunohistochemically positive for beta-human chorionic gonadotropin. Hence, the diagnosis of high-grade urothelial carcinoma with clear-cell (glycogen-rich) morphology and divergent trophoblastic differentiation was established. Patient outcome was poor. <b>Conclusions</b>: While conventionally having a somewhat favorable prognosis, special subtypes and divergent differentiation in urothelial carcinomas, which warrant a high-grade diagnosis are not only rare but also highly aggressive conditions. Further challenges arise in their differential diagnosis with other advanced malignancies, which can develop in adjacent organs in both genders.