Eosinophilic pulmonary granulomatosis resembling a pulmonary carcinoma in a dog in Hong Kong

Background: Canine Eosinophilic Pulmonary Granulomatosis (EPG) is a severe form of eosinophilic pulmonary disease that carries a guarded prognosis, responds poorly to therapy and recurs frequently. Most studies have reported a caudal lobar pulmonary distribution and a poorer prognosis in idiopathic cases.
Case Description: A 7-year-old dog was presented for persistent cough, hyporexia, and weight loss. Eosinophilia and basophilia were transiently present, and an antigen test for heartworm disease was negative. Radiographic studies, followed by a computed tomography (CT) scan revealed nodular lesions and a large mass in the left cranial lobar region suggestive of neoplasia. Cytological and histopathological evaluation was consistent with EPG. The dog responded positively to corticosteroids and has since remained free of disease.
Conclusion: EPG in dogs can resemble primary pulmonary neoplasia with secondary intra-pulmonary metastasis. Contrary to previous reports, idiopathic EPG can present with a cranial pulmonary distribution and respond positively to therapy.