Paraneoplastic focal segmental glomerulosclerosis in sarcomatoid renal cell cancer

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.

Paraneoplastic Glomerular Diseases

Paraneoplastic glomerular diseases (GNs) are rare manifestations in patients with underlying hematologic and solid organ malignancies and can occur before or after the detection of cancer. In the absence of established algorithms for investigation and reliable tests, they remain difficult to diagnose. Given the heterogeneity and infrequency of cases, the pathogenesis of most paraneoplastic GNs is poorly understood. Most of our recent understanding of paraneoplastic GNs has emerged from the discovery of target antigens in membranous nephropathy such as thrombospondin type-1 domain-containing protein 7A and neural epidermal growth factor-like 1 protein that appear to be promising in differentiating a primary vs paraneoplastic cause of membranous nephropathy. Treatment of paraneoplastic GNs is usually directed at the underlying malignancy. This review will focus on the epidemiology, pathogenesis, and diagnosis of paraneoplastic glomerular processes.

Paraneoplastic proteinuria in papillary renal cell carcinoma; a case report

We report a 55-year-old man presented with anemia and weakness, history of flank pain, hematuria and nephrotic syndrome. Spiral abdominopelvic computerized tomography (CT) scan showed multiloculated cystic mass (120 ×100 ×80 mm) in lower portion of left kidney with internal enhancing solid components and coarse peripheral calcifications. Radical nephrectomy of left kidney was done and biopsy confirmed renal cell carcinoma (RCC), papillary type, sarcomatoid foci, Fuhrman grade III. We assumed that, presence of nephrotic syndrome and paraneoplastic glomerulopathy leaded to heavy proteinuria in this case. Secondary, paraneoplastic glomerulopathy such as immunoglobulin A nephropathy and focal segmental glomerulosclerosis as a paraneoplastic syndrome of RCC have been reported previously. RCC can present with a wide range of signs and symptoms. Atypical presentations of papillary RCC such as proteinuria should be considered for patients presenting with nephrotic syndrome.