Obinutuzumab for the treatment of podocytopathy with concurrent suspected but unconfirmed B-cell lymphoproliferative disorder: a case report and literature review.

B-lymphocyte proliferative disorder have a certain incidence rate among the elderly. Whether these conditions require treatment is closely related to the presence of concurrent organ damage. This case report details the diagnostic journey and treatment process of a 76-year-old male patient who presented with nephrotic syndrome and acute kidney injury. His condition was further complicated by the presence of monoclonal M proteinemia and the malignant B-lymphocytes in the bone marrow. Through a series of examinations, a diagnosis of podocytopathy with suspected but unconfirmed B-cell lymphoproliferative disorder was established. Treatment involved with CD20 monoclonal antibody (Obinutuzumab). The patient achieved complete remission of proteinuria and normalization of renal function within one month, sustained at one-year follow-up. While the underlying mechanism remains uncertain, whether direct immunomodulation, B-cell clone control or both. This is the first reported case of successful treatment of podocytopathy with concurrent suspected but unconfirmed B-cell lymphoproliferative disorder using Obinutuzumab, offering a new therapeutic way for similar complex medical conditions.