JPC SYSTEMIC PATHOLOGY

RESPIRATORY SYSTEM

September 2017

P-M01

 

Signalment (JPC #2285063):  8-year-old female German shepherd dog

HISTORY:  This dog had a productive cough and progressive weight loss. Radiographic examination revealed consolidation of the right middle, caudal and accessory lung lobes.

HISTOPATHOLOGIC DESCRIPTION:  Lung: Effecting 60% of the section, effacing bronchioles and adjacent pulmonary parenchyma, there are multifocal to coalescing eosinophilic granulomas characterized by a central core of hypereosinophilic cellular and karyorrhectic debris (lytic necrosis) admixed with numerous degenerate eosinophils and fewer degenerate neutrophils.  Eosinophils often surround irregular bands or radiating spicules of brightly eosinophilic, hyalinized collagen (suggestive of flame figures). Necrotic foci are surrounded by epithelioid macrophages, eosinophils, lymphocytes, and plasma cells, which are further surrounded by a thick rim of fibroblasts and abundant collagen (fibrosis).  Eosinophilic granulomas are separated by   numerous alveolar macrophages, eosinophils, lymphocytes, and plasma cells admixed with moderate amounts of fibrin and edema, and lesser amounts of cellular and karyorrhectic debris, which obscure pulmonary architecture and fill adjacent alveoli.  Adjacent alveolar septa are thickened up to 4x normal by abundant fibrosis and low numbers of primarily macrophages and lymphocytes, with few plasma cells and eosinophils, and are occasionally lined by cuboidal pneumocytes (type II pneumocyte hyperplasia). Multifocally, the peribronchiolar and perivascular interstitia are expanded up to 5 times normal by dense fibrous connective tissue (fibrosis) and low numbers of previously described inflammatory cells. There is multifocal bronchiolar smooth muscle hypertrophy. Less affected alveoli contain increased numbers of foamy alveolar macrophages, while remaining bronchioles are often lined by hyperplastic epithelium and contain the previously described inflammatory exudate. The pleura is diffusely thickened, up to 1 mm in some areas, by fibrosis, ectatic lymphatic vessels, and low numbers of previously described inflammatory cells.

 

MORPHOLOGIC DIAGNOSIS:  Lung:  Eosinophilic granulomas, multifocal to coalescing, severe, with flame figures, marked fibrosis, and smooth muscle hypertrophy, German shepherd dog, canine

CONDITION:  Eosinophilic pulmonary granulomatosis (EPG)

SYNONYMS:  Pulmonary infiltrates with eosinophils, pulmonary eosinophilia (PE), eosinophilic pneumonia, and pulmonary hypersensitivity

GENERAL DISCUSSION:

PATHOGENESIS:

TYPICAL CLINICAL FINDINGS: 

TYPICAL GROSS FINDINGS:

TYPICAL LIGHT MICROSCOPIC FINDINGS:

ADDITIONAL DIAGNOSTIC TESTS: 

DIFFERENTIAL DIAGNOSIS:

COMPARATIVE PATHOLOGY: 

REFERENCES:

  1. Andrews SL, Bahr A. What is your diagnosis?.J Am Vet Med Assoc. 2008;232(4):505-506.
  2. Caswell JL, Williams KJ. Respiratory system. In: Maxie MG, ed. Jubb, Kennedy, and Palmer’s Pathology of Domestic Animals. Vol 2. 6th ed. Philadelphia, PA:Elsevier Saunders; 2016: 501-502.
  3. Clercx C, Peeters D. Canine eosinophilic bronchopneumopathy. Vet Clin North Am Small Anim Pract. 2007;37:917-935.
  4. Clercx C, Peeters D, Snaps F, et al. Eosinophilic bronchopneumopathy in dogs. J Vet Intern Med. 2000;14(3):282-291.
  5. Krafft E, Heikkilä HP, Jespers P, et al. Serum and bronchoalveolar lavage fluid endothelin-1 concentrations as diagnostic biomarkers of canine idiopathic pulmonary fibrosis. J Vet Intern Med.  2011;25(5):990-996.
  6. Percy DH, Barthold SW, Griffey SM. Pathology of laboratory rodents and rabbits. 4rd ed. Ames, IA: Blackwell Publishing;2016:160.
  7. Viitanen SJ, Laurila HP, Lilja-Maula LI, et al. Serum C-reactive protein as a diagnostic biomarker in dogs with bacterial respiratory diseases. J Vet Intern Med. 2014;28(1):84-91.   


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