Anti-dsDNA Positivity in a Patient with Prostate Cancer and Acute Kidney Injury: A Case Report

OBJECTIVE: Patients with malignancies may develop autoimmune and rheumatic manifestations as a result of generation of autoantibodies, paraneoplastic syndromes, direct invasion of joints and muscles by the tumour cells, or combination chemotherapy. We present a case with prostate cancer and acute kidney injury (AKI) mimicking rapidly progressive glomerulonephritis with a positive test result for anti-double-stranded deoxyribonucleic acid antibodies (Anti-dsDNA ab). CASE PRESENTATION: The 78-year-old male patient applied to our center with the complaint of generalized bone pain since approximately two months, and rapid onset of weakness, oliguria and dysuria for three days. He had been diagnosed metastatic prostate cancer (PC) for two years and at the time of application had received high dose of naproxen sodium because of severe bone pain for 5 days. Serum creatinine level was elevated on admission (2.4 mg/dl). Urinalysis revealed microscopic hematuria, granular casts and proteinuria of 1.2 gr/day. Immunologic tests including Anti-dsDNA antibody were done regarding acute nephritic syndrome. The subject was positive for Anti-dsDNA ab with a value of 96 IU/ml (normal, <10 IU/ml). Renal biopsy was planned but the patient refused the procedure. After 6 days of oliguric period, his clinical condition and renal functions returned almost to normal with supportive care within 12 days. CONCLUSION: Malignant diseases may be a trigger for either the generation of some autoantibodies. Attention must be paid when interpreting the Anti-dsDNA positivity in malignant patients with AKI mimicking RPGN.