An Unusual Case of Chronic Kidney Disease with Mediastinal Lymphadenopathy

Granulomatous interstitial nephritis (GIN) is a rare histological diagnosis seen in less than 1% of native renal biopsies. This case report describes a 37-year-old male with chronic kidney disease (CKD) and mediastinal lymphadenopathy. The kidney biopsy showed granulomatous interstitial nephritis with mild interstitial fibrosis and variable tubular atrophy, as well as a lymph node biopsy with non-caseating granulomas. All the etiologies for non-caseating granulomas, such as infections (mycobacterial, fungal, bacterial, viral infections), hypersensitivity reactions, autoimmune disorders, and granulomatosis with polyangiitis), were initially considered and later excluded as the workup was negative. The patient was unresponsive to a trial of steroids and continued to be on dialysis. This case highlights the importance of obtaining a kidney biopsy in patients with progressive renal dysfunction without traditional risk factors such as hypertension and diabetes.