INTRODUCTION: 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. CLINICAL PICTURE: 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. TREATMENT AND OUTCOME: 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. CONCLUSION: 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.