Arterial and Arteriolar Lesions in Renal Allografts: A Differential Diagnostic Approach

Abstract

Renal allograft pathology is quite a complex issue and has been addressed in many monographs and book chapters. Renal allografts can fail secondary to rejection, but recurrent renal diseases and de novo diseases affecting the allograft may also contribute to the demise of the transplanted kidney. As a pathologist, one needs to examine the four compartments of the kidney (glomeruli, tubules, interstitium, and vasculature) separately and integrate the histology with the clinical presentation. Although glomerular and tubulointerstitial changes can be quite relevant in terms of renal allograft outcome and prognosis, correct evaluation of arterial/arteriolar changes in a renal allograft is crucial in making the appropriate diagnosis and the arterial/arteriolar changes may provide relevant prognostic information. The pathologist should very carefully study and describe the vascular changes in a renal allograft and correlate them with clinical findings. If arteries are not present, or if only a single or two small terminal interlobular arteries are seen, the biopsy report should indicate this and draw attention to possible sampling errors and to limited informative value of the specimen. In this review, we will try to provide a short review on vascular changes in renal allografts with a differential diagnostic approach.