Nested Type Bladder Cancer: A Tricky Entity A Report of Two Cases

BACKGROUND: Urothelial carcinoma of the bladder is the most common malignant tumor of the urinary tract. The nested variant of urothelial carcinoma is a rare entity, and the incidence is reported to be between 0.3- 0.8%. This variant is characterized by a bland cytologic appearance that is misleading and discordant with its aggressive clinical behavior. CASES: We report 2 cases of nested type carcinoma which have come to our attention in the period 2006-2016 of about 2,700 cases of bladder cancer, paying attention to the elements that can help in the differential diagnosis and the treatment. In case 1 the patient underwent a radical cystoprostatectomy, and in case 2 it was proposed to the patient to undergo radical cystectomy, but he refused this treatment, so he has been placed under close follow-up without endovesical chemotherapy. CONCLUSION: A correct and early diagnosis, knowing all histological pitfall lesions, seems to be the only element able to improve the chances of survival of the patients affected by nested variant urothelial carcinoma. Certainly, the patient with this rare tumor should be advised of the adverse clinical course of his disease, and cystectomy is strongly recommended in these types of cases. (Anal Quant Cytopathol Histpathol 2017;39: 108-113) Keywords: Bladder, bladder cancer, differential diagnosis, malignant tumor of the urinary bladder, nested variant, therapy, urinary bladder cancer