APRIL 2019

Signalment (JPC #1176745):  Age and gender unspecified Sprague-Dawley rat

HISTORY:  Incidental finding

HISTOPATHOLOGIC DESCRIPTION:  Small intestine and mesentery:  Diffusely, mesenteric arteries are tortuous with lumina variably narrowed by markedly thickened walls which are expanded by reactive fibroblasts within the tunica media, collagen, numerous small caliber blood vessels, and clear space (edema) and which are transmurally infiltrated by numerous viable and degenerate neutrophils, fewer macrophages, lymphocytes, plasma cells, rare multinucleate giant cells, eosinophils, and necrotic debris (necrotizing vasculitis).  The internal elastic lamina is discontinuous and the tunica intima is markedly expanded by thick bands of deeply eosinophilic hyalinized fibrin admixed with cellular and karyorrhectic debris (fibrinoid necrosis) between the hypertrophied reactive endothelium and the internal elastic lamina.  Arterial lumina are rarely occluded by organizing fibrin thrombi.  Inflammatory cells and fibroblasts extend into the tunic adventitia, disrupt elastic fibers of the external elastic membrane, and extend into surrounding connective tissue, which contains many small caliber blood vessels and edema.  Multifocally, there is moderate atrophy of mesenteric fat with increased numbers of spindle to stellate cells (fibroblasts), edema and numerous small caliber blood vessels (granulation tissue).

MORPHOLOGIC DIAGNOSIS:  Arteries, mesenteric:  Arteritis, proliferative, fibrinoid and necrotizing, chronic-active, diffuse, severe, Sprague-Dawley rat, rodent.

CONDITION:  Polyarteritis nodosa

SYNONYMS:  Panarteritis; periarteritis nodosa; systemic necrotizing vasculitis









  1. Dincer Z, Piccicuto V, Walker UJ, Mahl A, McKeag S. Spontaneous and drug-induced arteritis/polyarteritis in the Göttingen minipig-review. Toxicol Pathol. 2018; 46(2):121-130.
  2. Ferreras MC, Benavides J, Fuertes M, et al. Pathological features of systemic necrotizing vasculitis (polyarteritis nodosa) in sheep. J Comp Pathol. 2013;149:74-81.
  3. Hamir AN, Palmer M, Li H, Staska J, Rogers DG. Spontaneous idiopathic arteritis of the testicular artery in raccoons (Procyon lotor). Vet Pathol. 2009;46:1129-1132.
  4. Robinson WF, Robinson NA. Cardiovascular system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. St. Louis, MO: Elsevier; 2016:70-71.
  5. Miller LM, Gal A. Cardiovascular system and lymphatic vessels. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:614-615.
  6. Mitchell RN. Blood vessels. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Philadelphia, PA: Elsevier Saunders Co; 2016:509-510.
  7. Percy DH, Barthold SW. Pathology of Laboratory Rodents and Rabbits. 4th ed., Ames, IA: John Wiley & Sons Inc; 2016:99,156.
  8. Pesavento PA, Dange RB, Ferreras MC, et al. Systemic necrotizing vasculitis in sheep is associated with ovine herpesvirus 2. Vet Pathol. 2019;56(1):87-92.
  9. Salvadori C, Vezzosi T, Marchetti V, Cantile C. Polyarteritis nodosa in a cat with involvement of the central and peripheral nervous systems. J Comp Pathol. 2019;167:6-11.
  10. Wessels M, Strugnell B, Woodger N, Peat M, La Rocca SA, Dastjerdi A. Systemic necrotizing polyarteritis in three weaned lambs from one flock. J Vet Diagn Invest. 2017;29(5):733-737.

Click the slide to view.

Click on image for diagnostic series.

Back | Home | Contact Us | Links | Help |