JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-B17

 

Signalment (JPC #2130811):  Beagle

HISTORY:  This dog was found dead.

HISTOPATHOLOGIC DESCRIPTION:  Pleura:  Diffusely, the pleura is expanded up to 10mm, often forming papillary projections, by granulation tissue, inflammation and areas of necrosis. Foci of lytic necrosis are characterized by loss of normal architecture with replacement by necrotic cellular debris, degenerate neutrophils, fibrin, and areas of drop-out, often centered on large (up to 1.5mm) mats of 2um, beaded, filamentous bacilli admixed with finely granular basophilic material (sulfur granules).  Surrounding necrotic areas and markedly expanding the surrounding pleura there are numerous viable and degenerate neutrophils, epithelioid macrophages, few multinucleated giant macrophages, and aggregates of lymphocytes and plasma cells, admixed with hemorrhage, fibrin, eosinophilic cellular and karyorrhectic debris, and abundant loose (edematous) to hyalinized fibrous connective tissue with plump reactive fibroblasts and numerous small caliber vessels (granulation tissue). Endothelial cells are diffusely hypertrophied (reactive), vessel walls are often expanded by previously described inflammatory cells, and there are scattered fibrin thrombi. Villous projections are multifocally lined by hypertrophied mesothelial cells that occasionally pile up to 3 cells deep (mesothelial hyperplasia).

MORPHOLOGIC DIAGNOSIS:  Pleura:  Pleuritis, proliferative, pyogranulomatous, and necrotizing, diffuse, severe, with granulation tissue, sulfur granules and large colonies of filamentous bacteria, beagle, canine.

ETIOLOGIC DIAGNOSIS:  Actinomycotic pleuritis

CAUSE:  Actinomyces sp.

GENERAL DISCUSSION:

PATHOGENESIS:

 TYPICAL CLINICAL FINDINGS:

 TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY:

REFERENCES:

  1. Biberstein EL, Hirsh DC. Pathogenic Actinomycetes (Actinomyces and Nocardia). In: Hirsh DC, Zee YC, eds. Veterinary Microbiology. Malden, MA: Blackwell Science, Inc; 1999:250-3.
  2. Britton AP, Zabek E, Schwantje H. J Zoo Wildl Med. 2011;42(4):751-4.
  3. Caswell JL, Williams KJ. Respiratory system. In: Maxie ME, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA: Elsevier; 2016:521-522.
  4. Lopez A, Martinson SA. Respiratory system, mediastinum, and pleurae. In: Zachary JF, ed. Pathologic Basis of Veterinary Disease. 6th ed. St. Louis, MO: Elsevier; 2016:557-8.
  5. Sykes JE. Actinomycosis and nocardiosis. In: Greene CE, ed. Infectious Diseases of the Dog and Cat. 4th ed. St. Louis, MO: Elsevier Saunders; 2012:484-90.


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