Idiopathic necrotising granulomatous interstitial nephritis.P Vaideeswar, BV Mittal
Department of Pathology, Seth G. S. Medical College, Parel, Mumbai - 400 012, India., India
Correspondence Address: Source of Support: None, Conflict of Interest: None PMID: 11832601
Source of Support: None, Conflict of Interest: None
We report a case of idiopathic necrotising granulomatous interstitial nephritis seen as an incidental autopsy finding in a 65 years female. The unusual features were the presence of necroses, with a florid, bizarre giant cell reaction. There were varying degrees of tubular damage, with relative sparing of glomeruli. There was no history of drug ingestion; Mycobacteria, fungi or crystals were not identified.
Keywords: Aged, Autopsy, Case Report, Female, Granuloma, pathology,Human, Kidney, pathology,Nephritis, Interstitial, pathology,
Granulomatous interstitial nephritis is an uncommon condition that occurs due to many infective and non-infective agents. The patients present with acute renal failure and the condition is usually diagnosed by renal biopsy. We report such a case found incidentally at necropsy that exhibited unusual features. The cause could not be ascertained.
A 65 years female was admitted in an unconscious state with decerebrate rigidity. There was no past history of ischaemic heart disease, hypertension, diabetes mellitus or any drug therapy. The clinical impression was of cerebrovascular accident. She died within one hour of admission.
A complete autopsy was performed, Both the kidneys were small (right 70 gm, left 65 gin) with abundant perinephric fat. The capsule was stripped with difficulty. The surface was finely granular and showed few, small pin-head sized, raised, firm, yellowish white areas, restricted to the thin cortex. Medulla, pelvicalyceal system, ureters and urinary bladder were normal. There were no calculi.
On microscopy, the white nodules were composed of aggregates of lymphocytes, neutrophils, few plasma cells and occasional eosinophils, amidst a background of necroses and early fibrosis. The more striking feature was the presence of multiple bizarre giant cells [Figure - 1]. These were as large as the glomeruli with haphazard or horse-shoe arrangement of nuclei and phagocytosis of inflammatory cells. There was disruption and necroses of the adjoining glomeruli and infiltration of an occasional arteriole. Elsewhere, there were areas of tubular necroses with regenerative hyperplasia and of tubulitis. Few tubular lumina contained giant cells, red cells and inflammatory cells. Hyaline fractured casts suggestive myelom protein were not seen. Special stains for Mycobacteria and fungi were negative. Immunoperoxidase staining for the tubercular antigen was also negative. Examination under polarized light did not reveal any crystals.
The renal arteries were normal. Other organs, including the lungs did not reveal any tuberculous foci or any other granulomatous reaction. Hilar lymph nodes were normal. There was moderate left ventricular hypertrophy. Death resulted from hypertensive haemorrhage in the mid-brain and pons.
Granulomatous interstitial nephritis is an infrequent morphology of cell mediated injury that one encounters in kidney biopsies. Such a reaction though rare, is mainly due to drug induced hypersensitivity. The drugs commonly implicated are antibiotics, diuretics or non-steroidal anti-inflammatory agents. These patients present with acute renal failure and can have allergic manifestations. The granulomas are devoid of necroses with orientation around, or, infiltration of, small blood vessels. Necrosis was evident in our case; there was no history of any drug ingestion thereby ruling out drug induced aetiology.
Due to the necrotic foci, our initial impression was a tuberculous involvement of the kidneys. Tuberculosis is rampant in our country. The earliest manifestation is miliary granuloma formation in the cortex due to glomerular involvement. However, here the kidney revealed a florid and bizarre giant cells that were present within the necrotic foci, instead of rimming them. They also exhibited lymphophagocytosis and were not accompanied by epithelioid cells. These unusual features did not correspond to the usual description of tuberculous granulomas. Special stains ruled out both tuberculous and fungal aetiologies.
Sarcoidosis as a cause of granulomas in the kidney biopsies must be kept in mind. We did not entertain this diagnosis owing to lack of clinical and microscopic features that are characteristic of sarcoidosis. Foreign body granulomatous reaction can occur in response to calcium oxalate crystals in nephrolithiasis, especially in case of small intestinal bypass. The reaction is again non-caseating, though there has been a report with pseudo-tuberculous granuloma. No crystals were identified in our case.
Granulomatous glomerulonephritis and arteritis has been described in a variety of settings like Wegener’s granulomatosis and microscopic polyarteritis. Such a reaction surrounds a glomerulus or vessel with necrotising changes. In the present case, involvement of a few glomeruli and occasional arterioles were secondary to the predominant interstitial involvement.
Lastly, there have been instances where the cause of renal granulomas were not known and were classified as idiopathic. Though the history of consumption of allopathic drugs was not present, a possibility of use of herbs and homeopathic medicine which has become a common practice in general population cannot be denied. We conclude that aetiology of granulomatous interstitial nephritis in our case could be categorised as idiopathic.
The authors are grateful to Dr. VS Venkatseshan, Department of Pathology, Barnert Hospital, New Jersey, USA for her valuable comments.
[Figure - 1]