Follicular cysts of the thyroid gland are one of the thyroid gland disorders, mostly due to dysfunction or long-term irritation from inflammation. Follicular cysts of the thyroid gland are one of the manifestations of thyroid cysts, mostly due to endocrine disorders or long-term stimulation by inflammation. It is usually benign and has a low chance of being malignant. Follicular thyroid cysts are cysts that grow on the thyroid gland, which contain fluid. Generally, follicular cysts in the thyroid gland grow very slowly, have a long course, and generally have no effect. If the thyroid follicular cysts are large, and if there is also pressure on the nerves, trachea, or esophagus causing difficulty in swallowing, hoarseness, difficulty in breathing, and irritability, surgery may be an option. Generally, single follicular cysts of the thyroid gland have an intact envelope and are clearly demarcated from the surrounding tissues, so there is usually no pain or pressure. In cases of enlarged follicular cysts, an enlarged mass may appear in the front of the neck, and an ultrasound may reveal an uneven echogenicity and surface heterogeneity of the thyroid gland. There may even be enlarged lymph nodes in the neck. Follicular thyroid cysts are usually benign, and if the mass is not large, it is important to keep an eye on it and follow up regularly. If the cyst is large or increases in size within a short period of time, it needs to be treated aggressively.