Renal Involvement in Indolent and Aggressive B-Cell Neoplasms: A Comparative Study of Chronic Lymphocytic...

Renal involvement is an uncommon but clinically important manifestation of B-cell neoplasms, and direct comparisons between indolent and aggressive entities remain limited. This single-center retrospective biopsy-confirmed and tissue-selected study compared 28 biopsy-confirmed patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) or diffuse large B-cell lymphoma/high-grade B-cell lymphoma (DLBCL/HGBL), with 14 patients in each group, treated at Peking University First Hospital between June 2010 and June 2025. The aggressive comparator group included 13 DLBCL cases and one case annotated as HGBL with MYC and BCL2 rearrangements. Clinical features, timing of renal involvement recognition, dominant clinical entry points, pathological patterns, treatment strategies, and hematologic and renal responses were analyzed. CLL/SLL was associated with higher white blood cell and absolute lymphocyte counts, whereas DLBCL/HGBL showed higher lactate dehydrogenase and β2-microglobulin levels. The interval to renal involvement recognition was longer in CLL/SLL than in DLBCL (24.00 vs. 2.00 months, p = 0.007). At renal involvement recognition or biopsy, 24 h urinary protein excretion was nominally higher in the CLL/SLL group than in the DLBCL/HGBL group (3.90 vs. 1.58 g/24 h). CLL/SLL more often presented with proteinuria/edema, hematuria, or renal dysfunction and showed heterogeneous infiltrative lesions with concurrent glomerular or vascular involvement. DLBCL/HGBL more frequently presented with flank pain or renal mass-related manifestations and was dominated by direct infiltrative or mass-forming lesions. Treatment patterns differed markedly, whereas no significant difference in the distribution of renal responses was detected; however, this comparison was underpowered and should be interpreted descriptively. In this biopsy-confirmed, tissue-selected cohort, CLL/SLL and DLBCL/HGBL showed different observed patterns of renal involvement recognition, tissue acquisition, and renal pathological presentation. These findings support tissue-based evaluation of renal abnormalities in B-cell neoplasms but should be interpreted as descriptive and hypothesis-generating in view of the small sample size and the influence of diagnostic and biopsy pathways.