Secondary urinary bladder involvement by diffuse large B-cell lymphoma presenting with obstructive acute kidney injury: A case study

Objective: To describe a rare case of secondary urinary bladder involvement by diffuse large B-cell lymphoma presenting as an infiltrative bladder mass with bilateral obstructive uropathy.
Methods: This single anonymized case study was prepared from clinical, radiological, endoscopic, histopathological and immunohistochemical data obtained during routine patient care. Written informed consent for publication was obtained.
Results: A 71-year-old woman with a remote history of treated breast cancer presented with lower urinary tract symptoms, gross hematuria, bilateral flank pain, asthenia and weight loss. Computed tomography showed severe bilateral ureterohydronephrosis caused by an approximately 5-cm infiltrative bladder mass involving both ureteral orifices. Bilateral nephrostomy was performed, followed by transurethral resection. Histopathology showed sheets of large atypical lymphoid cells, and immunohistochemistry demonstrated diffuse CD20 expression with a Ki-67 proliferation index of 80%, supporting diffuse large B-cell lymphoma. Staging revealed supra- and infradiaphragmatic lymphadenopathy and a suspicious subhepatic peritoneal lesion, consistent with secondary bladder involvement.
Conclusion: Secondary bladder lymphoma is a rare but clinically important differential diagnosis of an infiltrative bladder mass. Histopathology with immunohistochemistry is essential when bladder carcinoma and lymphoma cannot be distinguished clinically or radiologically.