# Primary B-cell lymphoma of the renal pelvis following robotic nephroureterectomy: a case report

## TL;DR

A rare case of primary B-cell lymphoma in the kidney was diagnosed after surgery, highlighting challenges in distinguishing it from kidney cancer.

## Contribution

This case report adds to the limited literature on primary renal lymphoma following robotic nephroureterectomy.

## Key findings

- A renal pelvis mass initially suspected as urothelial carcinoma was diagnosed as diffuse large B-cell lymphoma post-surgery.
- The case emphasizes the importance of biopsy for indeterminate renal lesions to avoid misdiagnosis.
- Primary renal lymphoma presents clinical similarities to upper tract urothelial carcinoma, complicating diagnosis.

## Abstract

We present a rare case of Primary Renal Lymphoma (PRL) diagnosed on histopathology following robotic nephroureterectomy. This case explores the diagnostic and management challenges urologists face, when treating renal masses.

An 82-year-old male presented with recurrent macroscopic haematuria and a computed tomography intravenous pyelogram (CT IVP) reported renal papillary necrosis and an associated mass effect at the right renal pelvis. Urine cytology was inconclusive, whilst inpatient pyeloscopy revealed a renal pelvis tumour. This was biopsied and reported as suspicious for urothelial carcinoma. Multidisciplinary team discussion (MDT) recommended curative surgery. Following right nephroureterectomy, postoperative histology revealed a diffuse large B-Cell lymphoma (DLBCL) extending through the renal capsule into perirenal fat, renal vein and renal pelvis.

We highlight the clinical similarities between upper tract urothelial carcinoma (UTUC) and PRL, encouraging urologists to consider biopsies of indeterminate lesions, particularly amongst the frail population.