Case report: Malignant chemodectoma with hepatic metastasis in a cat

Area of Science:

• Veterinary Pathology
• Oncology
• Comparative Medicine

Background:

• Chemodectomas are rare neuroendocrine tumors typically arising from the aortic arch or carotid bodies.
• Diagnosis in felines can be challenging due to their uncommon presentation and varied clinical signs.

Observation:

• A 10-year-old domestic short-hair cat presented with acute dyspnea.
• Sedation for thoracocentesis precipitated cardiopulmonary arrest, despite resuscitation efforts.
• Necropsy revealed severe pleural effusion, pulmonary atelectasis, and extensive multinodular masses in the heart and liver.

Findings:

• Histopathology identified a densely cellular neoplasm infiltrating the myocardium and major vessels, with similar metastatic nodules in the liver.
• Immunohistochemistry showed intense synaptophysin and variable chromogranin A reactivity in neoplastic cells.
• Neoplastic cells were negative for cytokeratin, vimentin, thyroglobulin, and smooth muscle actin.

Implications:

• The findings support a diagnosis of malignant chemodectoma with hepatic metastasis in this feline case.
• Synaptophysin and chromogranin A are identified as key immunohistochemical markers for diagnosing feline chemodectoma.
• This case underscores the potential for rapid clinical deterioration associated with this tumor in cats.