Granulomatous interstitial nephritis in granulomatosis with polyangiitis mimicking leprosy: A case report.

Granulomatous polyangiitis (GPA) is a small vessel vasculitis commonly affecting the upper and lower respiratory tracts and kidneys. About 90% of the cases are associated with ANCA, namely, PR3-ANCA and MPO-ANCA. Herein, we describe a patient of GPA who presented with anasarca, sensory neuropathy, recurrent upper airway congestion, epistaxis, and rapidly progressive glomerulonephritis. Granulomatous interstitial nephritis and necrotizing granulomatous inflammation of the nasal septum were found on biopsy of the kidney and nasal septum, respectively both of which are rare findings. PR3-ANCA and MPO-ANCA were negative. Fulfilling the ACR criteria, this case of GPA proves that biopsy is still the gold standard of diagnosis.