Passive liver congestion associated with caudal vena caval compression due to oesophageal leiomyoma

A large caudodorsal mediastinal mass was identified in a dog which had been presented for vomiting and anorexia. A few weeks later, the dog developed ascites and hindlimb oedema. Radiography showed that the caudodorsal mediastinal mass was compressing the caudal vena cava, probably inducing passive congestion of the liver. At postmortem examination, the mass was diagnosed as a large oesophageal leiomyoma. To the authors' knowledge, an oesophageal tumour leading to compression of the caudal vena cava associated with passive congestion of the liver has not been described previously in dogs. Secondary signs relating to the oesophageal mass appeared to be more prominent than the digestive signs. Causes of passive congestion of the liver and the differential diagnoses for a caudodorsal mediastinal mass are discussed.