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Abstract: SA-PO850

Paraneoplastic IgA Nephropathy Associated with Renal Cell Carcinoma

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Libre, Michael Alessandro, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
  • McCall, Natalie Nesmith, Vanderbilt University Medical Center, Nashville, Tennessee, United States
  • Triozzi, Jefferson Lorenzo, Vanderbilt University Medical Center, Nashville, Tennessee, United States
Introduction

Malignancy is a rare and underrecognized cause of secondary IgA nephropathy, particularly in elderly patients. We present a case of IgA nephropathy likely paraneoplastic to renal cell carcinoma (RCC) that resolved after tumor resection.

Case Description

A 71-year-old previously healthy woman presented to the nephrology clinic with an elevated serum creatinine. Although asymptomatic, the patient noted her son had IgA nephropathy requiring kidney transplant. On examination, she was hypertensive to 158/88 mm Hg but had a normal cardiopulmonary examination with no peripheral edema. Laboratory studies showed a serum creatinine elevated to 2.7 mg/dL from normal baseline. Urinalysis showed 100 mg/dL protein, large blood, 68 WBC/HPF, and 83 RBC/HPF. Serologic workup was unremarkable. A kidney ultrasound and subsequent MRI showed a mixed solid cystic mass measuring 4.6 x 4.1 x 3.8 cm involving the lower pole of the right kidney. A biopsy of the left kidney demonstrated IgA dominant immune complex glomerulonephritis with necrosis and crescents, for which she was treated with high dose prednisone. A biopsy of the right kidney mass identified clear-cell renal cell carcinoma, for which she underwent uncomplicated partial nephrectomy. Her kidney function subsequently stabilized allowing for discontinuation of steroids.

Discussion

IgA nephropathy can be associated with infection, autoimmune conditions, liver disease, and malignancies—such as lung cancers, lymphomas, IgA myeloma, and RCC. This case represents a paraneoplastic IgA nephropathy associated with clear cell RCC that resolved post-nephrectomy. Although fewer than ten cases related to RCC are reported in the literature, multiple studies have identified pathologic evidence of IgA nephropathy in RCC nephrectomy specimens. This suggests that IgA nephropathy may result from tumor-induced antigen-antibody response. The primary goal of treatment is to address the underlying malignancy to minimize the risk of further kidney damage and allow for recovery. The role of steroids or other immunosuppressive therapies is unclear. In this case, removing the tumor led to significant improvement possibly due to elimination of tumor-induced immune interactions.