<unk>  is a benign tumor of the thyroid gland.<unk>  was first discovered by Fabricius, in 1619 when he described that thyroid enlargement causes midline neck swelling.<unk>  may be classified according to the histology into 3 subtypes/groups follicular adenoma, papillary adenoma, and signet cell adenoma.<unk>  arises from epithelial cells of thyroid gland, that are normally involved in secretion of thyroxine hormone. The most common gene involved in the pathogenesis of<unk>  is THADA gene. Common causes of<unk>  include iodine deficiency, chronic inflammation, and genetic mutation of THADA gene.<unk>  must be differentiated from other thyroid disorders such as multinodular goiter, grave's disease, Hashimoto's disease, medullary cell carcinoma, De Quervain's thyroiditis, thyroid lymphoma, and acute suppurative thyroiditis. The incidence of<unk>  is estimated to be 9 million cases annually in United States. Females are more commonly affected with<unk>  than males. Common risk factors in the development of<unk>  are family history of<unk> , exposure to radiation, lack of iodine in diet, smoking, and Hashimoto's thyroiditis. Depending on the extent of the tumor at the time of diagnosis, the prognosis may vary. However, the prognosis is generally regarded as excellent. The hallmark of<unk>  is swelling in front of the neck. A positive history of radiation exposure and family history of<unk>   is suggestive of<unk> . The most common symptoms<unk>  include cough and hoarseness of voice. On ultrasound,<unk>  is characterized by halo sign or smooth margin of thyroid, hyperechoic nodules, and normal reactive cervical nodes. Fine needle aspiration biopsy may be helpful in diagnosis of<unk> . Findings on fine needle aspiration biopsy suggestive of<unk>  include cystic changes, fibrosis, and areas of hemorrhage. The mainstay of therapy for<unk>  is supportive therapy and regular monitoring.
Thyroid adenoma
Thyroid nodule
Papillary thyroid cancer
Medullary thyroid cancer
Follicular thyroid cancer
Parathyroid adenoma
Toxic multinodular goiter
Papillary carcinoma of the thyroid