Canine eosinophilic pulmonary granulomatosis: case report and literature review

Abstract

We describe and illustrate herein a case of eosinophilic pulmonary granulomatosis (EPG) in a 16-mo-old, castrated male, Great Pyrenees crossbred dog. EPG appears to differ from eosinophilic pneumonias and eosinophilic bronchopneumopathy in dogs by the presence of nodules and masses in the lungs composed of eosinophils, macrophages, and various combinations of lymphocytes, plasma cells, neutrophils, and mast cells within fibrous tissue. Specific information from this dog was added to the information from the limited number of other dogs diagnosed with EPG reported in the veterinary literature, and the information analyzed. EPG appears to have no breed or sex predilection and tends to be a disease of younger dogs, often ≤ 3 y of age. Antemortem imaging of nodules and masses in the lungs, combined with cytologic evidence of eosinophils in the lesions, is highly suggestive of EPG, and the diagnosis can be confirmed postmortem. Concurrent eosinophilia and basophilia can be features of EPG, but their diagnostic value requires further investigation, as does the possible causal association with Dirofilaria immitis infection.

Keywords: dogs; eosinophilic granuloma; lung pathology.

Figure 1.

Eosinophilic pulmonary granulomatosis in a dog. The cut surface of a large, firm, pale mass in the right lung.

Figure 2.

Eosinophilic pulmonary granulomatosis in a dog. A. Low-magnification photomicrograph of the mass. Many polymorphonuclear cells and other inflammatory cells are intermixed with bundles of collagen. H&E. Original objective 10×. B. Low-magnification photomicrograph of the mass highlighting the bundles of collagen. Masson trichrome. Original objective 10×. C. High-magnification photomicrograph of the mass demonstrating many eosinophils. Duffy. Original objective 100×.