Cranial mediastinal carcinomas in nine dogs*

Abstract

Nine dogs were diagnosed with cranial mediastinal carcinomas. Based on histological and immunohistochemical analysis, four dogs were diagnosed with ectopic follicular cell thyroid carcinomas, one dog with ectopic medullary cell thyroid carcinoma, two dogs with neuroendocrine carcinomas and two dogs with anaplastic carcinomas. Clinical signs and physical examination findings were associated with a space-occupying mass, although one dog was diagnosed with functional hyperthyroidism. Surgical resection was attempted in eight dogs. The cranial mediastinal mass was invasive either into the heart or into the cranial vena cava in three dogs. Resection was complete in six dogs and unresectable in two dogs. All dogs survived surgery, but four dogs developed pulmonary thromboembolism and two dogs died of respiratory complications postoperatively. Adjunctive therapies included pre-operative radiation therapy (n=1) and postoperative chemotherapy (n=3). Three dogs had metastasis at the time of diagnosis, but none developed metastasis following surgery. The overall median survival time was 243 days. Local invasion, pleural effusion and metastasis did not have a negative impact on survival time in this small case series.

Computed tomographic appearance of canine thyroid tumours

“…In two dogs, there were lung nodules on CT but not on radiographs. None of the thoracic CT scans showed abnormal tissue in the cranial mediastinum and cardiac regions where ectopic thyroid tissue has been most commonly described (Liptak et al , Kang et al ).…”

Underlying diseases in dogs referred to a veterinary teaching hospital because of dyspnea: 229 cases (2003–2007)

“…A range of breeds were included, with Bulldogs (n = 22), Labrador Retrievers (20), mixed breeds (19), and Cavalier King Charles Spaniels (19) being most common. A range of breeds were included, with Bulldogs (n = 22), Labrador Retrievers (20), mixed breeds (19), and Cavalier King Charles Spaniels (19) being most common.…”

“…3,16,17 Most of them were referred as routine cases, which is consistent with longer duration of clinical signs before initial examination and a better outcome for this group than for patients with other causes of dyspnea, likely because surgery significantly improves outcome. 10,11,13,19 Furthermore, dogs have an excellent collateral ventilation, which protects against airway obstruction; however, the ability to redistribute blood flow from poorer-to betterventilated regions of the lung may be limited. However, whereas age can help to predict etiology, this should not be the sole criterion for decision making, as highlighted by the finding that dogs with lymphoma were examined at a significantly younger age, as has been reported previously.…”

Canine Thyroid Tumors and Hyperthyroidism

“…In clinical studies, pulmonary metastasis is identified in 30% to 40% of dogs, which contrasts with histopathologic studies that report metastasis in up to 80% of dogs at time of death (Leav et al, 1976;Brodey and Kelly, 1968;Sullivan et al, 1987;Marks et al, 1994;Carver et al, 1995;Turrel et al, 2006). Neoplastic transformation of ectopic thyroid tissue may result in identification of a cranial mediastinal mass on pulmonary radiographs (Liptak et al, 2008). Computed tomography (CT) is more sensitive for detection of pulmonary metastasis than is radiography (Armbrust et al, 2012) and should be done prior to treatment planning.…”