A challenging radiographic diagnosis - extraluminal leiomyoma of the oesophagus in a small-sized dog: a case report

An 11-year-old, intact male Maltese dog presented with a history of vomiting and regurgitation. On plain radiographs, a caudodorsal thoracic mass was identified, and there were no radiographic signs frequently associated with an oesophageal mass. An oesophagram with fluoroscopy showed no classical signs of an oesophageal mass such as an irregular mucosal surface, a filling defect, or decreased ability of the lumen to pass contrast medium through the oesophageal lumen. A mass of pulmonary or mediastinal origin rather than of oesophageal origin was suggested. During the operation for mass removal, a gross connection between the suspected mass and the adventitia of the distal oesophagus was identified; thus, excision of the extraluminal mass was performed from the outer oesophageal wall. Histopathology confirmed the mass to be an oesophageal leiomyoma. This case highlights that the differentiation of an extraluminal oesophageal mass from other masses of mediastinal or lung origin can be challenging with radiographs and oesophagram alone. Even when the radiographic signs are not suggestive of an oesophageal mass, an extraluminal oesophageal mass should be considered.