JPC Systemic Pathology
April 2019

Signalment (JPC# 2370157):  A 1-year-old spayed female domestic shorthair cat

History:  This cat died unexpectedly 6 days after routine ovariohysterectomy. 

Histopathologic description:  Heart:  Diffusely, expanding the endocardium of the left ventricle up to five times normal (50um) and infiltrating and separating subjacent myofibers, there is abundant eosinophilic beaded to fibrillar material (fibrin), hemorrhage, and clear space (edema), admixed with moderate numbers of fibroblasts, neutrophils, lymphocytes, plasma cells, macrophages, and eosinophilic cellular and karyorrhectic debris (necrosis).  Multifocally, inflammatory cells infiltrate the underlying myocardium, expand the interstitium, and separate, surround, and replace cardiomyocytes that are occasionally either swollen and vacuolated (degenerate), or shrunken with hypereosinophilic sarcoplasm, loss of cross striations, and pyknotic nuclei (necrotic).

Morphologic diagnosis:  Heart, left ventricle:  Endocarditis, fibrinous, subacute, diffuse, moderate, with edema, hemorrhage, and multifocal myocarditis, domestic shorthair cat, feline.

Etiologic diagnosis:  Idiopathic endocarditis

CAUSE:  Unknown

CONDITION:  Endomyocarditis (EMC)



TYPICAL Gross findings:

TYPICAL LIGHT Microscopic findings:

Differential diagnosis:

For cardiac disease in cats:

Comparative pathology

Valvular endocarditis:



  1. Barthold SW, Griffey SM, Percy DH. Pathology of Laboratory Rodents and Rabbits. 4th ed. Ames, IA: Wiley Blackwell; 2016: 99, 241-242.
  2. Donovan TA, et al. Bartonella as a possible cause or cofactor of feline endomyocarditis-left ventricular endocardial fibrosis complex. J Comp Pathol. 2018;162:29-42.
  3. Kimura Y, et al. Pathological features and pathogenesis of the endomyocardial form of restrictive cardiomyopathy in cats. J Comp Pathol. 2016;155(2-3):190-198.
  4. McEndaffer L, Molesan A, Erb H, Kelly K. Feline panleukopenia virus is not associated with myocarditis or endomyocardial restrictive cardiomyopathy in cats. Vet Pathol. 2017;54(4):669-675.
  5. Miller LM, Van Vleet JF, Gal A. Cardiovascular system and lymphatic vessels. In: Zachary JF, McGavin MD eds. Pathologic Basis of Veterinary Disease. 5th ed. St. Louis, MO: Elsevier Mosby; 2012: 588.
  6. Robinson WF, Robinson WF. Cardiovascular system. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 3. 6th ed. Louis, MO: Elsevier; 2016: 46-47.

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