Renal Diffuse Large B-cell Lymphoma Mimicking Acute Pyelonephritis on 18 F-FDG PET/CT

Area of Science:

• Oncology
• Radiology
• Nephrology

Background:

• Renal masses can present diagnostic challenges, potentially mimicking infectious or inflammatory conditions.
• Diffuse large B-cell lymphoma (DLBCL) is an aggressive non-Hodgkin lymphoma that can rarely involve the kidneys.

Purpose of the Study:

• To report a case of renal DLBCL that mimicked pyelonephritis on 18F-FDG PET/CT.
• To emphasize the utility of PET/CT in differentiating renal lymphoma from infection and guiding diagnostic biopsies.

Main Methods:

• A 58-year-old male patient with urolithiasis history presented with fever and pollakisuria.
• 18F-FDG PET/CT was performed due to ineffective empirical anti-infective therapy.
• Biopsies of the axillary lymph node and kidney were conducted for histopathological confirmation.

Main Results:

• 18F-FDG PET/CT revealed bilateral renal enlargement with nodular cortex uptakes and an enlarged left axillary lymph node, initially suggestive of pyelonephritis.
• Histopathological analysis confirmed high-grade diffuse large B-cell lymphoma (DLBCL) in both the lymph node and kidney.
• The patient achieved sustained remission after R-DA-EPOCH chemotherapy.

Conclusions:

• Renal DLBCL can present with imaging findings similar to pyelonephritis on 18F-FDG PET/CT.
• PET/CT plays a vital role in the diagnostic workup of suspected renal malignancies, aiding in targeted biopsy and accurate diagnosis.
• Early and accurate diagnosis through PET/CT-guided biopsy is essential for effective management of renal lymphoma.