Isolated Granulomatous Renal Arteritis: A Variant Form of Giant Cell Arteritis with Few Macrophages

A 64-year-old woman with hypertension and hyperlipidemia was admitted to our hospital for the investigation and management of general fatigue, anorexia, a 5-kg weight loss, and a 4-week history of high-grade fever. She had no symptoms of headache, myalgia, or arthralgia, and the physical examination was unremarkable. The laboratory tests revealed renal dysfunction with urine abnormalities that had not been observed 1 year earlier. A renal biopsy showed granulomatous small arteritis without necrotic lesions or glomerular pathology. An immunohistochemical study of the infiltrating leukocytes showed a predominance of CD4+ T cells followed by CD8+ T cells, and only a few macrophages. The condition drastically improved after treatment with 30 mg/day of oral prednisolone. The granulomatous renal arteritis was considered a variant of giant cell arteritis, because it showed the peculiar finding of a few macrophages in the granulomatous lesions.