Pauci-immune crescentic glomerulonephritis associated with metastatic rectal carcinoma

Paraneoplastic glomerular disease is well recognised, although it most frequently presents with clinical features of the nephrotic syndrome. This case describes a 74-year-old male with metastatic rectal adenocarcinoma treated surgically with anterior resection followed by adjuvant capecitabine chemotherapy. Having previously had normal renal function, he developed an acute kidney injury with active urinary sediment following the discovery of liver metastases. A renal biopsy was performed, which revealed an active crescentic pauci-immune glomerulonephritis. The patient was treated with high dose oral corticosteroids which led to some improvement in renal function, although he was still left with significant kidney impairment, which limited further safe oncological treatment. This case highlights a rare presentation of glomerular disease in the setting of malignancy and also demonstrates the adverse impact that kidney impairment can have on outcomes in patients with cancer.