Metastasis of colon cancer to the thyroid and cervical lymph nodes: a case report

The incidence of thyroid metastasis among colorectal cancer patients is extremely rare. We report a case of colonic adenocarcinoma metastasis to the thyroid gland with treatment of lung and liver metastases, in a 61-year-old woman with a history of colon cancer. She showed a thyroid mass related to a 3-month history of hoarseness. Physical and imaging examinations disclosed a diffuse large thyroid mass with swollen cervical lymph nodes. Fine-needle aspiration cytology of the thyroid mass suggested malignancy. The patient underwent total thyroidectomy. Histopathological examination and immunohistochemical staining revealed adenocarcinoma, which was consistent with a diagnosis of metastases from primary colon cancer to the thyroid and cervical lymph nodes. At 2 years after thyroid surgery, the patient has been continuing outpatient chemotherapy for the lung and liver metastases. Thyroidectomy appeared to both relieve the patient and prevent local symptoms.