Pediatric renal artery dysplasia: a morphologic study.

Renal arteries from 12 pediatric patients who had stenosis due to renal artery dysplasia (9 surgical resections and 3 autopsy cases) were examined by light microscopy. The patients ranged in age from 15 months to 14 years; the male/female ratio was one. Bilateral renal artery disease was clinically diagnosed in 8 of the 12 patients; 6 of the 8 also had aortic anomalies. All of the lesions were designated as forms of dysplasia, a departure from previous reports in which dysplasia was subclassified as fibroplasia and hyperplasia. The most common lesion was medial fibrous dysplasia (6), followed by perimedial elastic dysplasia (4); intimal fibrous dysplasia (1) and medial muscular dysplasia (1) were the least common. Medial fibrous dysplasia was present as often with bilateral as with unilateral renal artery stenosis, while perimedial elastic dysplasia was seen exclusively in patients with bilateral renal artery disease. Three patients who came to autopsy had extrarenal vascular involvement by a similar dysplastic lesion. The three patients who had neurofibromatosis showed no distinctive histologic type of renal artery dysplasia.