Secondary malignancy of the thyroid gland is uncommon, but it is a problem requiring ongoing recognition. As it is more common than primary thyroid malignancy, metastatic disease involving the thyroid gland should be actively excluded in a patient with enlarging or abnormal thyroid gland and a previously known primary tumour.We report 2 cases of primary colon carcinoma with metastasis to the thyroid gland that mimicked thyroid anaplastic carcinoma. In both cases, airway compromise was evident.Emergency tracheostomy was necessary in the first case with subsequent oxaliplatin-based chemotherapy providing palliation of symptom of breathlessness, with significant reduction in size of thyroidal metastasis. Palliative thyroidectomy relieved airway compromise in the second case.Our case report highlights the importance of early recognition of thyroidal metastases from a colonic primary as life-threatening airway compromise may otherwise rapidly ensue.
