1. Introduction

Lymphomas are a heterogeneous group of hematologic malignancies that most commonly involve nodal structures but can present extranodally in disparate organ systems. Although genitourinary involvement by lymphoma is uncommon, ureteral involvement and consequent obstruction have been reported in case reports and small series, underscoring the need for awareness among clinicians and pathologists when evaluating obstructive uropathy of unclear etiology [1–6]. Unfortunately, diagnostic work‐up for patients with ureteral lymphoma continues to be a significant challenge due to various causes of obstruction that mimic its presentation [7, 8]. Ureteric calculi, strictures, and urothelial carcinoma are some etiologies that present in a similar fashion on modalities such as ureteroscopy or pyelogram [7, 8]. The ureter represents a particularly rare site for primary involvement, with primary ureteral lymphomas described infrequently and often mimicking more common urothelial or extrinsic compressive processes [1, 3, 5]. Here, we describe an unusual presentation of extranodal marginal zone lymphoma causing acute ureteral obstruction. In our patient case, she had no evidence of previous malignancy but presented with acute flank pain and was found to have complete ureteral obstruction.