Follicular carcinoma of the thyroid is a malignant tumor characterized by follicular cell differentiation. Pathologic findings are inconsistent, mostly seen in women above middle age, rarely with lymphatic metastasis, manifested as nodular goiter. 1. Pathology: follicular carcinoma accounts for 15%~20% of thyroid carcinoma, the pathology is inconsistent in various parts, some tissues are almost normal, some only have nuclear division, and invasion of blood vessels and tissues near blood vessels is common, which is more significant in elderly patients. Most of them are mixed with papillary carcinoma in a mixed pattern. The degree of malignancy is different, but higher than papillary carcinoma. 2. Age of onset: mostly seen in middle-aged or above women, with history of radiotherapy to the neck in childhood. 3. Metastatic pathway: lymphatic metastasis is rare, but there can be hematogenous distant spread, especially easy to spread to bones, lungs, liver and other organs. 4. Clinical manifestations: the main manifestation is nodular goiter, which is large in size, hard as stone, and common in single nodule. Follicular cell carcinoma and its metastatic foci have iodine uptake function, and may occasionally cause hyperthyroidism. In the later stage, invasion of adjacent tissues, pain, and distant metastasis may occur. Patients with follicular carcinoma of thyroid should go to the hospital for consultation in time and standardize the treatment under the guidance of doctors.