Lymphoma as a Rare Cause of Ureteral Obstruction: A Case Report.

Extranodal marginal zone lymphoma involving the urinary system is a rare manifestation of lymphoma. Ureteric obstruction by this subtype of lymphoma can mimic other more common genitourinary or retroperitoneal conditions. The current case describes a 42-year-old female who presented with abdominal pain and hydronephrosis without findings supportive of renal or ureteric calculus. Diagnostic work-up was unremarkable, even with the employment of endoscopic evaluation. The patient's ureter was dilated and she underwent both stenting and eventual percutaneous nephrostomy tube placement. Ultimately, she underwent surgical intervention with ureteral reimplantation and associated histopathological analysis was able to definitively diagnose a low-grade B-cell extranodal marginal zone lymphoma. The present case highlights the diagnostic challenges associated with this rare etiology of urinary obstruction. It also emphasizes the importance of considering atypical malignancy in the differential diagnosis of recurrent ureteral obstruction, especially when traditional radiological imaging and clinical assessment are unrevealing.