Granulomatosis with Polyangiitis Masquerading as Renal Mass: Case Report and Literature Review

Wegener's granulomatosis or granulomatosis with polyangiitis (GPA) is multisystemic vasculitis. Kidney involvement in GPA often presents with rapidly progressive renal failure and requires urgent treatment. A 60-year-old female presented with prolonged history of fever, generalized weakness, decreased appetite, and weight loss over 4 months. Her renal function was normal; urine culture was sterile. On further evaluation, she was found to have large, hypodense solid lesion in mid pole of the right kidney on CECT. CT guided renal biopsy was done, which showed granulomatous interstitial nephritis with focal crescents. On further evaluation, she was found to have high titers of anti-MPO antibody. She was started on steroid and methotrexate with subsidence of fever. Follow-up after 12 months showed resolution of the lesion. GPA solely presenting as solid mass like lesion in the kidney is extremely rare presentation. Early diagnosis and prompt initiation of the treatment can prevent the progression of the disease.