Sudden growth of a lump in the neck, mostly due to diseases occurring in the thyroid gland, which is located in the anterior part of the neck, manifests as a locally raised lump with pain, usually a thyroid adenoma complicated by intra-tumoral hemorrhage. It is a benign disease of the thyroid gland with mild localized tenderness, smooth surface, clear boundaries, and good up and down movement with swallowing. The most effective treatment is surgery, which can be performed under local or general anesthesia. The lesion is removed intact, taking care to avoid collateral damage to the gland and adjacent tissues, and a postoperative pathological examination is required. Benign thyroid diseases, including simple adenomas or cysts, are associated with compensatory hyperplasia of the thyroid follicles and are considered to be benign lesions secondary to iodine deficiency in the body, which affects thyroxine metabolism.