Paraneoplastic Glomerulonephropathy Associated With Renal Cell Carcinoma: A Descriptive Analysis of Published Reports.

Paraneoplastic glomerulonephropathy (PGN) is a rare paraneoplastic syndrome that is associated with a variety of malignancies. Patients with renal cell carcinomas (RCCs) often develop paraneoplastic syndromes including PGN. To date, objective diagnostic criteria of PGN are not defined. As a result, the true occurrences are unknown. Many RCC patients develop renal insufficiency in the course of their disease, and diagnosis of PGN in this population is challenging and often delayed, which may lead to significant morbidity and mortality. Here, we provide a descriptive analysis of the clinical presentation, treatment, and outcomes of 35 published patient cases of PGN associated with RCCs over the past four decades in PubMed-indexed journals. Most patients with PGN were male (77%), over 60 years of age (60%), and diagnosed with PGN prior to or concurrent with their diagnosis of RCC (20% prior, 71% concurrent). Membranous nephropathy (34%) was the most common pathologic subtype. Among the patients with localized RCCs, 16 (67%) of 24 patients had improvement in PGN compared to 4 (36%) of 11 patients with metastatic RCCs. All 24 patients with localized RCCs underwent nephrectomy, but patients who were treated with nephrectomy with immunosuppression (7/9, 78%) had a better outcome than patients who were treated with nephrectomy alone (9/15, 60%). Among the patients with metastatic RCCs, patients who were treated with systemic therapy along with immunosuppression (4/5, 80%) had a better outcome than those who were treated with systemic therapy, nephrectomy, or immunosuppression alone (1/6, 17%). Our analysis demonstrates the importance of cancer-specific therapy; nephrectomy in localized disease and systemic therapy in metastatic disease, along with immunosuppression, was the effective management of PGN. Immunosuppression alone is not adequate in most patients. This is distinct from other glomerulonephropathy and warrants further study.