Dr Sadia Jahan1, Dr Michael Bai2, Dr Bee Qung Tan2
1CNARTS, Adelaide, Australia, 2Renal Unit, Lyell McEwin Hospital, Adelaide, Australia
Background
The relationship between anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and malignancy is complex. Combined studies have identified a standardized incidence ratio of cancer in vasculitis between 1.6-2.0. This increased risk has been primarily attributed to the long-term effects of immunosuppression. Mitigating malignancy risk in both the short and long term remains one of the significant challenges in AAV treatment. The finding of an incidental neoplasm on renal biopsy occurs in approximately 0.2% of cases and can further complicate treatment options.
Case Report
A 52-year-old Cambodian man presented with a 2-month history of lethargy, sinusitis, arthralgia/myalgia, and microscopic haematuria with a recent diagnosis of hypertension. The investigations revealed creatinine 132μmol/L, proteinuria 1.78g/24 hours and positive ANCA-MPO titre 62IU/mL. Renal biopsy showed simultaneous AAV renal injury and an incidental finding of neoplastic proliferation, positively staining for renal markers (PAX8 and CA-IX) but negatively staining for prostate markers (NKX3 and PSAP), consistent with clear cell renal cell carcinoma (RCC). Imaging showed PET avidity in the prostate but not in the kidneys. Subsequent prostate biopsy ruled out malignancy. He was treated with pulse methylprednisolone and maintained on prednisolone monotherapy. At 24-months, his surveillance CT did not show RCC progression with creatinine 122 μmol/L and ANCA-MPO titre 14IU/mL.
Conclusion
Beyond staging and histopathological identification, there remains little evidence to guide the best course of therapy in these cases. In our patient, the decision to treat solely with corticosteroid was based on the concern of malignancy progression and the patient’s clinical improvement without cyclophosphamide induction.
Biography:
Bio to come