JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
September 2018
D-F02

SIGNALMENT (JPC Accession #1142242):  Cow

HISTORY:  None

HISTOPATHOLOGIC DESCRIPTION:  F02-A:  Rumen:  Extending transmurally from the mucosa into the tunica muscularis and serosa is a focally extensive wedge-shaped area of coagulative necrosis characterized by retention of tissue and cellular architecture, loss of differential staining.  Within the affected and adjacent areas, the vessel walls to include tunica media and adventitia are expanded by lymphocytes, plasma cells, macrophages, and fewer neutrophils, as well as fibrin, edema, karyorrhectic and cellular debris (necrotizing vasculitis).  Vascular lumina are occluded by fibrin admixed with cellular and karyorrhectic debris (fibrinthrombi) and multiple fungal hyphae, which extend through the tunica media into the surrounding perivascular space.  Fungal hyphae are 5-15 um wide, pauci-septate, with non-parallel walls, non-dichotomous, irregular or right angle branching, and bulbous dilatations.  The infarcted area is bound transmurally by a 5 mm thick band composed of degenerate and viable neutrophils, macrophages, lymphocytes, plasma cells, and eosinophilic cellular and karyorrhectic debris (lytic necrosis) that multifocally extend into and replace tunica muscularis and expand into overlying serosa. The epithelium adjacent to the infarct is thickened up to 3 times normal with prominent anastomosing rete ridges (epithelial hyperplasia), intracellular and intercellular edema, multifocal erosions and ulceration, and intraepithelial aggregates of degenerate and viable neutrophils (microabscesses).  The lamina propria, submucosa, and serosa are markedly expanded by increased clear space and ectatic lymphatics (edema), inflammatory cells, and fibrin.

F-02B  Gomori methenamine silver (GMS):  Rumen:  Multifocally throughout the tissue, there are GMS-positive fungal hyphae.

MORPHOLOGIC DIAGNOSIS:  Rumen: Rumenitis, necrotizing, acute, focally extensive and transmural, severe, with infarction, necrotizing vasculitis, fibrin thrombi, and numerous non-septate GMS-positive fungal hyphae, breed not specified, bovine.

ETIOLOGIC DIAGNOSIS:  Ruminal zygomycosis

CAUSE:  Zygomycetes spp.

CONDITION:  Mycotic rumenitis

GENERAL DISCUSSION: 

PATHOGENESIS: 

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS: 

TYPICAL LIGHT MICROSCOPIC FINDINGS: 

DIAGNOSIS:

DIFFERENTIAL DIAGNOSIS: 

Mycotic rumenitis

COMPARATIVE PATHOLOGY: 

REFERENCES:

  1. Chandler FW, Kaplan W, Ajello L. Color Atlas and Text of the Histopathology of Mycotic Diseases. Lochem, NL: Wolfe Medical Publications; 1980: 122-126, 294-300.
  2. Dyer NW, Newell TK. Mycotic Rumenitis in American Bison (Bison bison). J Vet Diagn Invest. 2002; 14(5):414-416.
  3. Gelberg HB. Alimentary System and the Peritoneum, Omentum, Mesentery, and Peritoneal Cavity. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:394.
  4. Jang SS, Walker RL. Fungal diseases. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO: Elsevier Saunders; 2012: 683-684.
  5. Jensen HE, Olsen SN, Aalbaek B. Gastrointestinal aspergillosis and zygomycosis of Cattle. Vet Pathol. 1994; 31:28-36.
  6. Songer JG, Post KW. Veterinary Microbiology, Bacterial and Fungal Agents of Animal Disease. St. Louis, MO: Elsevier Saunders; 2005: 398-401.
  7. Uzal FA, Platter BL, Hostetter JM. Alimentary System. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. 6th ed. St. Louis, MO: Elsevier; 2016: 40-43.
  8. Vermunt JJ, West DM. Fusobacterium necrophorum, Dichelobacter (Bacteroides) nodosus and Bacteroides spp. infections. In: Coetzer JAW, Tustin RC, eds. Infectious Diseases of Livestock. 3rd ed. Oxford, UK: Oxford University Press; 2004: 1738-1741.


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