Urinary bladder collision tumors: A case report and literature review

A collision tumor of the urinary bladder refers to a very rare condition in which two distinct types of tumors occur simultaneously within the same bladder. The present study reports the case of a patient with a collision tumor in the urinary bladder. A 43-year-old female patient was referred following a diagnosis of bladder carcinoma. The patient had previously undergone a cystoscopy-directed transurethral resection of a bladder tumor (TURBT) to remove a mass from the urinary bladder. A biopsy revealed that the tumor was a moderately differentiated T2-adenocarcinoma. A contrast-enhanced computed tomography (CT) scan revealed an irregular, thickened bladder wall. Based on the PET scan result and the initial TURBT result, which revealed T2-stage adenocarcinoma, a radical cystectomy was recommended. The final histopathological diagnosis was poorly differentiated adenocarcinoma (pT2 N0 M0) and well-differentiated squamous cell carcinoma T1 N0 M0 as a collision tumor. In addition, the present study also provides a literature review which summarizes cases of urinary bladder collision tumors in male patients aged 50 to 74 years, primarily presenting with hematuria. Diagnoses were confirmed using imaging techniques, such as CT scans and MRIs. Surgical treatments, including TURBT and radical cystectomy, are commonly used, with some cases also receiving chemotherapy or immunotherapy. Outcomes varied, with some patients experiencing recurrence or metastasis, while others remained recurrence-free post-surgery. A bladder collision tumor is a rare disease; extensive radiological study and careful examination of the biopsy are required to diagnose the condition.