Peritracheal intrathoracic granuloma in a Thoroughbred mare

Peritracheales intrathorakales Granulom bei einer Vollblutstute

Brünker S, Peters M, Wohlsein P, Odenkirchen S

DOI: 10.21836/PEM20130106
Year: 2013
Volume: 29
Issue: 1
Pages: 37-42

A seven-year-old thoroughbred mare was presented because of coughing and dyspnoe during exercise. The general condition was nor- mal. Rectal temperature, heart and respiratory rate were within physiological ranges. Conspicuous was a slight dyspnoe and an inspirato- ry tracheal breathing disorder extending the neck. Endoscopic examination revealed a dorsoventral compression of the trachea cranial to the bifurcation and a slight right dorsolateral compression of the oesophagus. The x-rays showed a well circumscribed, opaque mass in the area of the aortic arch. The trachea and the main bronchial tubes as well as the oesophagus were dorsally compressed. For further diagnostic positive contrast radiographs barium sulfate were taken. The mass that made the compression of the oesophagus didn’t take up any barium sulphate itself. The non-ionic contrast medium iopromid was injected intravenously. The mass didn’t show any radiographic uptake of the iopromid. The mare was sent home with a two weeks antibiotic treatment. The general condition progressively deteriorated, tachypnoe and severe dyspnoe appeared. Auscultation indicated inspiratory and expiratory tracheal breathing noises as well as tracheo- bronchial vesicular breathing noises at the right thorax. Endoscopy and radiographic examination revealed an almost total compression of the trachea. The mare was euthanized because of poor prognosis. Pathomorphologic examination showed a 16 x 11 x 10 cm mass dor- sal of the bifurcatio trachea which was well seperated from the lung tissue. Pathohistologically a chronic granulomatous inflammation with central necrosis was found. In the mucous membrane of the trachea a defect and a pyogranulomatous inflammation of the submucosa could be diagnosed in the area of the mass. The aspiration a foreign body and the isolated bacterium Shewanella putrefaciens may be involved in the pathogenesis of this lesion. Peritracheal abscesses, chronic suppurative lymphadenitis and pneumonia, primary lung tumors, pulmonary metastasis, oesophageal diverticulum and aortic aneurysm have be considered as differential diagnoses.