JPC SYSTEMIC PATHOLOGY
DIGESTIVE SYSTEM
September 2018
D-B15

SIGNALMENT:  (AFIP 3064906): Female weaner pig

HISTORY:  D-B15A This animal is from a group of weanlings pigs all with loose stools and fair body condition.

HISTOPATHOLOGIC DESCRIPTION:  Large intestine:  Multifocally there are elevated pedunculated plaques of mucosa, up to 3mm, composed of severely dilated and hyperplastic, tortuous crypts, with diffuse expansion of the lamina propria by a lymphoplasmocytic and eosinophilic infiltrate, increased clear space, and ectatic blood vessels and lacteals (congestion and edema). Diffusely, there is marked epithelial hyperplasia of the crypts characterized by elongated epithelial cells up to 7-8 cell layers thick that have crowded, often overlapping basophilic nuclei and frequent mitotic figures. There is an overall decrease in goblet cells.  Multifocally, crypts are dilated, lined by attenuated epithelium, and contain numerous nondegenerate and degenerate neutrophils, sloughed epithelial cells and cellular and nuclear debris (crypt abscesses). Multifocally there are small amounts of fibrin and debris adherent to the superficial mucosa as well as focal areas of hyperplastic crypt epithelium directly adjacent to the muscularis mucosa.

MORPHOLOGIC DIAGNOSIS:  Large intestine:  Enteritis, proliferative and lymphoplasmacytic, chronic, multifocal, moderate, with crypt ectasia and goblet cell loss, breed unspecified, porcine.

SIGNALMENT:  (#2415686): A ferret

HISTORY:  D-B15B None

HISTOPATHOLOGIC DESCRIPTION:  Colon:  Multifocally, the mucosa is markedly hyperplastic and forms papillary, adenomatoid projections that extend up to 2mm into the lumen and are composed of deep, often tortuous crypts lined by hyperplastic epithelium with plump, elongated cells with cytoplasmic basophilia,vesiculate nuclei that pile up to 4-5 cells layers thick, and frequent mitotic figures within all layers of the villi. There is a marked paucity of goblet cells. Multifocally, crypts are dilated, lined by attenuated epithelium, and contain numerous nondegenerate and degenerate neutrophils, sloughed epithelial cells and cellular and nuclear debris (crypt abscesses). The lamina propria and submucosa are moderately expanded by lymphocytes, plasma cells, neutrophils and macrophages with few eosinophils.

D-B15C (Warthin Starry):  Colon:  There are many argyrophilic, curved 1x5um bacilli concentrated in the apical cytoplasm of hyperplastic mucosal and glandular epithelial cells.

MORPHOLOGIC DIAGNOSIS:  Colon:  Colitis, proliferative, chronic, multifocal, moderate, with goblet cell loss, crypt abscesses, and numerous argyrophilic intraenterocytic bacilli, consistent with Lawsonia intracellularis infection, ferret (Mustela putorius furo), mustelid.

SIGNALMENT:  (#1547835) An adult hamster

HISTORY:  D-B15D Presented with diarrhea.

HISTOPATHOLOGIC DESCRIPTION:  Ileum: In approximately 75% of the tissue section there is a loss of differential staining with retention of tissue architecture (coagulative necrosis) and/or complete loss of normal tissue architecture with replacement by necrotic debris (lytic necrosis) admixed with fibrin, hemorrhage and edema; necrosis extends transmurally thru the intestine wall from mucosa to serosa in some areas, and only affects the mucosa in other areas. In areas bordering the coagulative and lytic necrosis, individual enterocytes show cytoplasmic hypereosinophilia, with nuclear pyknosis and karyolysis(necrosis). In the remaining tissue, there are deep, often tortuous crypts and irregularly hyperplastic, blunted, and fused villi. Multifocally in the non-necrotic ileum there is marked mucosal  hyperplasia with formation of papillary projections that extend up to 2mm into the intestinal lumen. Hyperplastic mucosal epithelium is characterized by cytoplasmic basophilia, vesiculate nuclei that pile up to 5-6 cell layers thick, frequent mitotic figures in all layers and decreased numbers of goblet cells. The lamina propria is mildly expanded by a lymphoplasmocytic infiltrate with rare histiocytes. Multifocally the crypt epithelium herniates through the lamina propria, into the submucosa and abuts the external muscular tunics.

MORPHOLOGIC DIAGNOSIS:  Ileum: Ileitis, proliferative and necrotizing, chronic, diffuse, severe, with crypt abscesses and herniation, hamster (Mesocricetus auratus), rodent.

ETIOLOGIC DIAGNOSIS:  Lawsonial enterocolitis

CAUSE:  Lawsonia intracellularis

CONDITION:  Proliferative enteritis, porcine proliferative enteropathy (pigs), proliferative bowel disease (ferret), proliferative ileitis (hamster)

SYNONYMS:  Porcine intestinal adenomatosis, proliferative ileitis, regional ileitis, garden hose disease (pig), acute proliferative hemorrhagic enteropathy, necrotic enteritis

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS:

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ULTRASTRUCTURAL FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Barthold SW, Griffey SM, Percy DH. Pathology of Laboratory Rodents and Rabbits. 4th ed. Ames, Iowa: John Wiley & Sons, Inc.; 2016:58,139-140,183-185,226,279-280.
  2. Guedes RM, Machuca MA, et. al. Lawsonia intracellularis in pigs: Progression of Lesions and Involvement of Apoptosis. Vet Pathol. 2017. 54(4):620-628.
  3. Ohta T, Kimura K, et. al. Proliferative enteropathy caused by Lawsonia intracellularis in chickens. J Comp Pathol. 2017. 156:158-161.
  4. 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 Ltd; 2016:177-180.
  5. Vannucci FA, Gebhart CJ. Recent advances in understanding the pathogenesis of Lawsonia intracellularis infections. Vet Pathol. 2014. 51(2):465-477.
  6. Zachary JF. Mechanisms of Microbial Infections. In: McGavin MD, Zachary JF, eds. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2017:164-165.


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