Obesity and Nested Urothelial Carcinoma of the Bladder: Falsely Bland Tumor in Young Man. A Rare Case Report and Literature Review

Background: Nested urothelial carcinoma of the bladder is an invasive histological variant that differs from classical urothelial carcinoma. It is a rare cancer, particularly among young people, with a prevalence of 0.3%; its bland histological character makes it less recognized, delays the diagnosis and compromises its prognosis. Causal link of this cancer and obesity is not usual in young subjects. About a case and review of the literature, we define its aggressiveness and its care dilemma especially for young people. Case Presentation: He was a 38-year-old obese man who was consulted for hematuria preceded by dysuria for six months. Ultrasound revealed a bladder tumor and moderate left uretero-hydronephrosis. On cystoscopy, the papillary tumor extended towards the left ureteral meatus. The patient underwent transurethral resection of the bladder tumor and histological findings were in favor of nested variant urothelial carcinoma of the bladder. On the extension assessment by thoraco-abdomino-pelvic CT scan, the tumor was at an advanced stage with the presence of pulmonary and spinal metastases. The evolution was unfavorable: the tumor did not regress in size under chemotherapy with Gemcitabine and Cisplatin. Conclusion: Imbricated variant carcinoma of the bladder is underdiagnosed and rare, particularly in young people. The cause and effect between this cancer and obesity deserves further investigation. It remains a public health problem and poses a major challenge in diagnosis, late treatment and often unfavorable prognosis.