Recognizing isolated IgG4-related nephropathy.

IgG4-related tubulointerstitial nephritis is an uncommon cause of renal impairment. It has been associated with dysfunction in a number of other organs giving rise to the term IgG4-related systemic disease; organ involvement can occur metachronously, hence, making it more difficult to identify patients. The exact cause of this condition remains unknown. Here, we present a case of isolated renal involvement which demonstrates how particular biochemical, radiological and histopathological changes should raise the suspicion of IgG4-related nephropathy, especially when there is an absence of clues from any other organ.