JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
October 2018
D-T03

Signalment (JPC #1851823):  1.5-year-old Holstein heifer    

HISTORY:  One batch of corn that was fed four to six weeks prior to this animal’s death was noticeably moldy.

HISTOPATHOLOGIC DESCRIPTION:  Liver:  Approximately 60% of the hepatic parenchyma is characterized by loss of normal hepatic chord architecture with hepatocytes being replaced by abundant fibrous connective tissue (fibrosis) and increased numbers of small bile ducts lined by epithelial cells with a high nuclear to cytoplasmic ratio and loss of nuclear polarity (ductular reaction).  Individual hepatocytes are multifocally shrunken, dissociated and hypereosinophilic with pyknotic or karryrhectic nuclei (necrosis). Remaining hepatocytes are disorganized and two to three times normal size and have abundant eosinophilic, vacuolated cytoplasm and large vesicular nuclei with marginated chromatin and a prominent nucleolus (megalocytosis); there is moderate aniokaryosis.  There are multifocal regenerative nodules which measure up to 1mm in diameter, lack portal areas, compress adjacent hepatocytes and are composed of disorganized hepatic cords surrounded by fibrosis.  Regenerative hepatocytes often contain clear intracytoplasmic vacuoles that are up to 20 um in diameter and peripheralize the nucleus (lipid type vacuolar change).  There are scattered aggregates of neutrophils, lymphocytes, plasma cells, fewer histiocytes and eosinophils, and rare single hepatocellular necrosis.  Multifocally, portal lymphatics are mildly ectatic (edema).

MORPHOLOGIC DIAGNOSIS:  Liver:  Hepatocellular necrosis and loss, chronic, diffuse, severe, with fibrosis, biliary ductular reaction, megalocytosis and nodular regeneration with lipid type vacuolar change, Holstein, bovine.

ETIOLOGIC DIAGNOSIS:  Hepatic aflatoxicosis

CAUSE:  Aflatoxin (mycotoxin B1) elaborated by Aspergillus flavus

CONDITION:  Aflatoxicosis

SYNONYM:  Groundnut poisoning

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Arana S, Alves VA, Sabino M, et al. Immunohistochemical evidence for myofibroblast-like cells associated with liver injury induced by aflatoxin B1 in rainbow trout (Oncorhynchus mykiss). J Comp Pathol. 2014; 150(2-3): 258-265.
  2. Baker DC, Green RA. Coagulation defects of aflatoxin intoxicated rabbits. Vet Pathol. 1987; 24(1): 62-70.
  3. Berry CL. The pathology of mycotoxins. J Pathol. 1988; 154(4): 301-311.
  4. Boulianne M, et al. Avian Disease Manual. 7th ed. Jacksonville, FL: AAAP; 2013:150-151, 251.
  5. Brown DL, Van Wettere AJ, Cullen JM. Hepatobiliary system and exocrine pancreas. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:450.
  6. Diseases of the liver. In: Constable PD, Hinchcliff KW, Done SH, Grunberg W, eds. Veterinary Medicine, A Textbook of the Diseases of Cattle, Horses, Sheep, Pigs, and Goats. 11th ed. St. Louis, MO: Elsevier; 2017:649-650.
  7. Hoerr FJ. Mycotoxicoses. In: Swayne DE, ed. Diseases of Poultry. 13th ed. Ames, IA: John Wiley & Sons, Inc.; 2013:1276-1279.
  8. Hollinger K, Ekperigin HE. Mycotoxicosis in food producing animals. Vet Clin North Am Food Anim Pract. 1999;15(1): 133-165.
  9. Massey TE, Smith GB, Tam AS. Mechanisms of aflatoxin B1 lung tumorigenesis. Exp Lung Res. 2000; 26(8): 673-683.
  10. Osweiler GD, Ensley SM. Mycotoxins in grains and feeds. In: Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, eds. Diseases of Swine. 10th ed. Ames, IA: John Wiley & Sons, Inc.; 2012:938-943.
  11. Pereyra MLG, Carvalho CQ, Tissera JL. An outbreak of acute aflatoxicosis on a chinchilla (Chinchilla lanigera) farm in Argentina. J Vet Diagn Invest. 2008; 20(6): 853-856.
  12. Qian G, Wang F, Tang L. Integrative toxicopathological evaluation of aflatoxin B1 exposure in F344 rats. Toxicol Pathol. 2013; 41(8): 1093-1105.
  13. Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. St. Louis, MO: Elsevier; 2016:333-334..
  14. Wouters ATB, Casagrande RA, Wouters F, et al. An outbreak of aflatoxin poisoning associated with aflatoxin B1-contaminated maize products. J Vet Diagn Invest. 2013; 25(2): 282-287.


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