Renal Dysfunction in Patients With Direct Infiltration by B-Cell Lymphoma

International audienceBackgroundB-cell lymphoproliferative disorders with renal involvement are relatively frequent, but remain poorly described. A kidney biopsy is usually required to detect the renal lesions that are often missed using other diagnostic tools.MethodsWe retrospectively identified 34 patients with renal lymphoma diagnosed by percutaneous kidney biopsy (PKB) at Rennes University Hospital and its affiliated hospital centers between January 1, 2004, and May 1, 2016. Clinical, biological, radiological, and histological characteristics were collected at biopsy time.ResultsThe included patients had Waldenström macroglobulinemia (n = 12; 35.3%), chronic lymphocytic leukemia/lymphocytic lymphoma (n = 10; 29.5%), high-grade B-cell lymphoma (n = 6; 17.6%), and low-grade B-cell lymphoma (n = 6; 17.6%). The median follow-up was 29 months. Renal involvement led to renal function impairment in 29 patients (85.3%), among whom 20 had acute kidney injury (70%), and to nephrotic syndrome in 4 patients (11.8%). Only 13 patients (38.2%) presented morphological kidney anomalies among whom 5 showed bilateral infiltration. Histologically, interstitial infiltrate (97.1%) was the most common kidney lesion, and 9 patients (26.5%) had specific lymphomatous intraglomerular lesions. After hematological treatment (n = 29), a renal response was observed only in 8 patients (27.6%).ConclusionRenal involvement in the context of B-cell lymphoproliferative disorders is not uncommon. PKB is the best method to confirm this diagnosis. It should be performed early to rapidly initiate the hematological treatment to preserve kidney function