Esophageal and gastric pythiosis in a dog

Abstract

Pythiosis is the disease caused by aquatic oomycetes of the genus Pythium. In dogs the typical course of the disease involves the gastrointestinal tract, characterized by transmural thickening of the stomach or intestines. However, infection by Pythium spp. has only rarely been recognized as a cause of esophagitis in dogs. Thus, the present reports a case of esophageal and gastric pythiosis in an eight-month-old female pit bull dog. The dog was attended at the hospital after two months presenting regurgitation and dyspnea. It was reported that the dog lived in an urban area and had no previous sanitary issues. At clinical examination it was noted that the dog presented crackling sounds at pulmonary auscultation. A support therapy accompanied by antibiotics has been employed; however, 22 days after hospitalization the clinical condition worsened, and the dog died. At necropsy, the wall of the distal segment of the esophagus and the cardia and part of the fundus of the stomach were expanded by a focal extensive irregular intramural annular mass. Additionally, there was a transmural esophageal fistula. At histology, the walls of the esophagus and stomach were extensively expanded by multifocal extensive areas of necrosis, associated with a pyogranulomatous infiltrate and abundant granulation tissue containing multiple negative images of hyphae that were highlighted by silver impregnation (Grocott). Furthermore, immunohistochemistry and PCR for P. insidiosum were both positive in samples of paraffin-embedded esophageal tissue.