Primary Aortic Chondrosarcoma in a Dog

interstitial fibrosis was prominent and associated with a mild lymphocytic inflammatory infiltrate. Occasional immature glomeruli were present. There was multifocal sclerosis of mature glomerular tufts with adhesions to Bowman's capsule. Other mature glomeruli were enlarged and had mesangial cell hyperplasia that formed an arboreal pattern. Other organs were histologically normal. The diagnosis of renal dysplasia was based on the presence of immature glomeruli, primitive tubules, atypical tubular epithelium (adenomatoid), and persistent mesenchyme. These features have been characterized in human renal dy~plas ia ' .~ and have been recently documented in multiple cases of canine renal dy~plas ia .~ The histological features in this case suggest that the induction of a metanephric blastema was initiated but failed to achieve complete differentiation.l.4.5 Hyperplastic tubular epithelium and hyperplastic mesengial cells are frequently encountered compensatory changes in renal dy~plas ia .~ As is frequent in canine renal dysplasia, concurrent extra-renal anomalies were not present in this There was no history of other horses related to this colt affected with renal disease, although canine renal dysplasia is often familial.24 References 1 Kissane JM: Congenital malformations. In: Pathology of the Kidney, ed. Heptinstall RH, 2nd ed., pp. 69-120. Little, Brown, and Co, Boston, 1974 2 Nash AS, Kelly D F, Gaskell C J: Progressive renal disease in soft-coated Wheaton terriers: possible familial nephropathy. J Sm Anim Pract 25479-487, 1984 3 O'Brien TD, Osborne CA, Yano BL, Baines DM: Clinicopathologic manifestations of progressive renal disease in Lhasa Apso and Shih Tzu dogs. J Am Vet Med Assoc 180:658-664, 1982 4 Picut CA, Lewis RM: Microscopic features of canine renal dysplasia. Vet Pathol 24: 156-163, 1987 5 Welling LW, Grantham JJ: Cystic and developmental diseases of the kidney. In: The Kidney, ed. Brenner BM and Rector FC, 3rd ed., vol. 2, pp. 1341-1376. WB Saunders, Philadelphia, I986