JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
October 2018
D-T06 (NP)

Signalment: (JPC #2019285):  9-month-old castrated Merino sheep

HISTORY:  This sheep was dosed with a toxic preparation over a 25-day period.  During the last 3 days the animal became increasingly weak and was anorectic.

HISTOPATHOLOGIC DESCRIPTION:  Liver:  Diffusely hepatic cord and sinusoidal architecture is disrupted by swollen, vacuolated, haphazardly arranged hepatocytes (degeneration) that are often separated by moderate to abundant fine, loose fibrous connective tissue.  Some hepatocytes are large, with abundant granular eosinophilic cytoplasm and a large vesiculate nucleus, and occasional multinucleation. Others are individualized with a shrunken hypereosinophilic cytoplasm and a pyknotic or karyorrhectic nucleus (necrotic) or have intracytoplasmic round, variably sized discrete clear vacuoles (lipid-type degeneration).  Mitotic figures average 1 per HPF and bizarre mitoses are common.  Portal areas contain increased numbers of bile ducts (biliary hyperplasia) and are expanded by low numbers of lymphocytes.  Occasionally bile ducts and bile canaliculi contain brown to bright yellow globular material (cholestasis).  Multifocally, macrophages are distended with intracytoplasmic bright yellow to brown pigment (bile or hemosiderin). Multifocally lymphatics are ectatic (edema).

MORPHOLOGIC DIAGNOSIS:  Liver:  Hepatocellular degeneration and necrosis, chronic, diffuse, severe, with fibrosis, lipid-type degeneration, bizarre mitoses, multinucleated hepatocytes, biliary hyperplasia, and edema, merino, ovine.

ETIOLOGY:  Phomopsin mycotoxin

ETIOLOGIC DIAGNOSIS:  Phomopsin hepatopathy

CONDITION:  Mycotoxicosis

GENERAL: 

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY: 

REFERENCES: 

  1. Brown DL, Van Wettere AJ, Cullen JM. Hepatobiliary system and exocrine pancreas. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. Elsevier Mosby; 2017:450.
  2. Cullen JM, Stalker MJ. Liver and Biliary System. In: Maxie MG, ed. Jubb, Kennedy and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier Ltd; 2016:334-335.


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