Final Diagnosis -- Chronic Lymphocytic Interstitial Nephritis, Non-Hodgkin's Lymphoma, B-Cell Type

FINAL DIAGNOSIS:

KIDNEY, LEFT, PERCUTANEOUS NEEDLE BIOPSY:
1. NON-HODGKIN'S LYMPHOMA, B-CELL TYPE, FOLLICULAR CENTER ORIGIN (CD20 POSITIVE, CD10 POSITIVE), DIFFUSELY INFILTRATING PERIRENAL TISSUE AND RENAL CAPSULE.

2. CHRONIC LYMPHOCYTIC INTERSTITIAL NEPHRITIS INVOLVING RENAL PARENCHYMA, WITH ASSOCIATED MODERATE TO SEVERE CHRONIC PARENCHYMAL CHANGES (see comment).

The biopsy shows a lymphomatous infiltrate involving the perirenal soft tissues and renal capsule, a diagnosis supported by the immunophenotype of the lymphocytes marking as B-cells of follicular center cell origin.

On the other hand, the renal parenchyma shows a chronic interstitial nephritis with the Lymphocytic infiltrate marking predominantly as T-cells rather than B-cells; parenchymal chronicity changes are moderately severe. It is likely that the patient has two concurrent processes, ie lymphomatous perirenal infiltrate and chronic interstitial nephritis, the latter possibly related to chronic NSAID use.

Electron microscopy is not performed on this biopsy, since there is no evidence to suggest a concurrent glomerular process.

PATHOLOGY PEARLS:

• Primary lymphoma of genitourinary system is rare as these organs do not contain lymphoid tissue.
• Secondary involvement often occurs as a result of direct invasion or metastatic spread.
• Secondary involvement of genitourinary system is more common in non-Hodgkin's lymphoma than in Hodgkin's lymphoma. The most commonly affected organ is kidney followed by bladder and testis.
• Four main diagnostic criteria are recognized for clinical definition of renal involvement in the course of NHL:
  1. Bilateral localization.
  2. Various degree of renal failure with hypertension.
  3. Mild proteinuria.
  4. No other evident cause of renal abnormality.
• Causes of renal failure in NHL:
  1. Diffuse infiltration of both kidneys with tubular compression atrophy.
  2. Damage of normal renal structures by tumor derived lymphokines. (IL-2,TNF)
  3. Lower tract (ureteral) obstruction.
  4. Urate nephropathy.
  5. Cast nephropathy. (amyloid,light chain disease)
  6. Cryoglobulinemia.
  7. Hypercalcemia.
• Causes of proteinuria in NHL:
  1. Minimal change disease.
  2. Membranous glomerulopathy.
  3. Amyloid/Light chain deposit disease.
  4. Fibrillary/Immunotactoid glomerulopathy.
  5. Cryoglobulinemia.
• Histological pattern of renal involvement in cases of leukemia/lymphoma (Images 09 and 10)
  1. Infiltrative process. (usually low grade lymphoma)
  2. Nodular pattren. (usually high grade lymphoma)
• No significant correlation proved to exist between histological grade of NHL and metastases.
• Systemic chemotherapy and radiation produces rapid renal improvement.

REFERENCES:

1. Bertoncelli C etal. Parenchymal renal involvement in three cases of Non-Hodgkin Lymphomas:Clinical and Pathological features.Haematologica 1993;78:58-60.
2. Charasse C etal. Non-Hodgkin's Lymphoma presenting as Acute Renal Failure:A new case. Nephron 1996; 73:350-351.
3. Hemal A.K,Sharma S.K. Urological Complications of Advanced Lymphoma.Urol Int 1994;52:77-81.
4. Miyake o etal. Secondary Involvement of Genitourinary Organs in Malignant Lymphoma.Urol Int 1987;42:360 -362.

Contributed by Swaminathan Rajendiran,MD and Sheldon Bastacky, MD