Bilateral Thyroid Carcinosarcoma in a Cat.

Area of Science:

• Veterinary Pathology
• Oncology
• Comparative Pathology

Background:

• Primary hyperthyroidism is common in cats, but rapidly growing cervical masses require further investigation.
• Thyroid carcinosarcoma is a rare malignant neoplasm typically seen in dogs and humans.

Observation:

• A domestic shorthaired cat presented with a rapidly growing cervical mass and a history of hyperthyroidism.
• Cytology suggested sarcoma, but post-mortem examination revealed bilateral thyroid carcinosarcomas infiltrating the trachea.
• Histopathology confirmed thyroid carcinosarcoma with positive immunohistochemical markers for vimentin, pan-cytokeratin, and thyroid transcription factor-1.

Findings:

• This case represents the first documented instance of thyroid carcinosarcoma in a feline patient.
• The neoplasm was characterized by bilateral thyroid gland enlargement and infiltration of adjacent structures.
• A concurrent, unrelated pulmonary adenocarcinoma was also identified.

Implications:

• This report expands the known spectrum of thyroid neoplasms in domestic animals.
• It highlights the importance of thorough post-mortem examination for diagnosing rare conditions.
• Further research into feline thyroid carcinosarcoma may improve diagnostic and therapeutic strategies.