Cranial mediastinal carcinoma

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Thoracic radiographs of a dog with ectopic thyroid carcinoma[1]

Cranial mediastinal carcinoma are mediastinal tumors that produce an anterior mass in the chest of dogs.

A number of types of carcinoma can affect the anterior mediastinum, including:

  • Ectopic follicular cell thyroid carcinoma[2]
  • Medullary cell thyroid carcinoma
  • Neuroendocrine carcinoma
  • Anaplastic carcinoma[3].
  • Thymic branchial cyst carcinoma[4]

Clinically affected dogs invariably present with symptoms referable to an intrathoracic mass. Inspiratory dyspnea, stridor, coughing, vomiting, weight loss and anorexia are common.

Transcutaneous thoracocentesis may show variable degree of hemothorax or pyothorax.

Diagnosis is usually based on percutaneous biopsies and histological analysis of sampled tissue.

A differential diagnosis would include mediastinal lipoma, pulmonary carcinoma, bronchial carcinoma, thymoma, lymphoma, Coccidioides spp and Nocardia spp.

Radiographs usually reveal a visible mediastinal mass, often accompanied by secondary cardiomegaly, pulmonary edema.

In most cases, surgical excision of tumor is indicated, but is accompanied by a guarded to poor prognosis due to frequent metastases.


  1. Kang MH et al (2012) Ectopic thyroid carcinoma infiltrating the right atrium of the heart in a dog. Can Vet J 53(2):177-181
  2. Slensky KA et al (2003) Acute severe hemorrhage secondary to arterial invasion in a dog with thyroid carcinoma. J Am Vet Med Assoc 223(5):649-653
  3. Liptak JM et al (2008) Cranial mediastinal carcinomas in nine dogs. Vet Comp Oncol 6(1):19-30
  4. Levien AS et al (2010) Transformation of a thymic branchial cyst to a carcinoma with pulmonary metastasis in a dog. J Small Anim Pract 51(11):604-608