# Primary Renal Lymphoma: A Rare Cause of Bilateral Renal Enlargement and Acute Renal Failure in a Patient With Rheumatoid Arthritis

## TL;DR

This paper reports a rare case of primary renal lymphoma causing kidney failure in a patient with rheumatoid arthritis, emphasizing the need for timely diagnosis and treatment.

## Contribution

The paper presents a rare clinical case of primary renal lymphoma associated with rheumatoid arthritis and highlights its diagnostic challenges.

## Key findings

- Primary renal lymphoma can present as bilateral renal enlargement and acute renal failure.
- Renal biopsy confirmed non-Hodgkin diffuse large B-cell lymphoma in the patient.
- Treatment with R-CHOP led to full recovery of kidney function at one-year follow-up.

## Abstract

Primary renal lymphoma (PRL) is a rare non-Hodgkin's lymphoma (NHL) involving the kidneys without evidence of extra-renal involvement. We describe a 66-year-old female who presented with bilateral pleural effusions, and acute renal failure and was diagnosed with primary renal diffuse large B-cell lymphoma (DLBCL). She presented with shortness of breath due to bilateral pleural effusions and acute renal failure. Computed tomography (CT) of the chest reported bilateral pleural effusions. Thoracocentesis and subsequent fluid analysis reported non-malignant effusion. Her kidney function worsened during her hospital stay, requiring dialysis. Nonspecific findings such as bilateral renal enlargement on imaging prompted a renal biopsy. Histopathology reported mixed tubulointerstitial atypical lymphocytic CD 20 and BCL-6 positive cell infiltrates, confirming non-Hodgkin diffuse large B-cell lymphoma. Whole-body positron emission tomography/CT (PET/CT) and brain magnetic resonance imaging (MRI) ruled out the involvement of any other organs or lymph nodes, confirming our diagnosis of PRL. She was treated with six cycles of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Her kidney function recovered fully and remained normal at the one-year follow-up. We highlight the importance of recognizing PRL as an underlying cause of renal failure and its association with autoimmune diseases. Prompt investigation with timely diagnosis and treatment can result in improved morbidity and mortality in these patients.