A challenging case: Esophageal leiomyoma in a dog

These clinicians discovered that a senior dog's respiratory problems were caused by a benign but sizable esophageal tumor.
Nov 01, 2008

Vital Stats
A 13-year-old 35.2-lb (16-kg) neutered male bichon frise was referred to the Veterinary Emergency Clinic in Toronto, Ontario, for evaluation of a caudal thoracic mass that had been identified radiographically by the referring veterinarian. The dog had a history of a chronic cough, panting of four to six weeks' duration, and intermittent dyspnea. Prior medical therapy included orbifloxacin, theophylline, and prednisone. The dog's vaccination status was current, and it was receiving a monthly heartworm preventive.


On physical examination, the dog was slightly overweight. Mild dental disease was present, and mildly increased respiratory noise was noted on auscultation. The dog's temperature and heart and respiratory rates were normal. The results of a complete blood count were normal. A serum chemistry profile revealed slight hypercalcemia (3.01 mmol/L; reference range = 2.2 to 3 mmol/L). Urinalysis revealed hematuria, with 10 to 20 RBCs/HPF, which was attributed to the cystocentesis.

Figure 1. A ventrodorsal thoracic radiograph reveals a mass in the dog's right caudal thorax (arrow).
Thoracic radiographs obtained by the referring veterinarian revealed a 4-cm mass in the right caudodorsal thorax (Figure 1). Computed tomography (CT) showed a round 4.5-cm-diameter mass that appeared to be intraluminal in the caudal esophagus (Figure 2). The mass was well-circumscribed but slightly irregular on the right side, where it came in contact with the pulmonary parenchyma. We could not completely exclude the possibility of local invasion but considered it unlikely because the lungs appeared normal. A fine-needle aspirate was not attempted because of the mass's central location.

Figure 2. A transverse CT view of the dog's thorax (at the level of eighth rib) reveals a mass (arrow) just caudal to the heart and associated with the esophagus.
Our initial differential diagnoses included primary malignant esophageal neoplasia (i.e. fibrosarcoma, squamous cell carcinoma, or leiomyosarcoma), benign esophageal neoplasia (i.e. leiomyoma), esophageal granuloma, and metastatic esophageal neoplasia. We recommended esophagoscopy with possible biopsy.