Renal Lymphoma Diagnosed on Kidney Biopsy Presenting as Acute Kidney Injury

Introduction: Renal manifestations associated with hematolymphoid malignancies are known. Primary or secondary involvement of the kidney by lymphomatous infiltration has various clinical presentations. Acute kidney injury is not an uncommon finding in relation to lymphomatous interstitial infiltration proven on kidney biopsy. However, diagnosing it solely on renal biopsy remains a challenge and needs expertise and aid of immunohistochemistry as the prognosis is dismal. Methods: This is a retrospective study of kidney biopsy-proven cases of renal lymphoma presenting with acute kidney injury. Results: The study included 12 patients with ages ranging from 4 to 50 years who presented with serum creatinine ranging 2.1-9.6 mg%. Renal biopsy findings showed interstitial lymphomatous infiltrate. Two cases were diagnosed as primary lymphoma and the other 10 as secondary lymphomas. Among the 12 cases, nine were B-cell non-Hodgkin lymphoma, of which diffuse large B-cell lymphoma was diagnosed in six (50%), low-grade B-cell type in two (16.6%), chronic lymphocytic leukemia in one (8.3%), and three were T-cell-type. Two were acute T-cell lymphoblastic lymphoma and one other was a high-grade T-cell lymphoma. Four patients succumbed. The other four patients are alive; one is on chemotherapy, while two of them are on hemodialysis. Conclusion: Acute kidney injury as a presenting feature with lymphomatous infiltration of renal parenchyma is not uncommon. The patchy involvement makes it challenging on kidney biopsy with definitive diagnosis being made with the help of immunohistochemistry. Appropriate multidisciplinary involvement improves patient outcome.