What is thyroglossal duct cyst?

Most common developmental anomaly of thyroid gland, most common congenital neck mass, may be evident after adulthood. Due to persistent cystic dilation of thyroglossal duct, embryonic tract characterized by presence of epithelial lined remnants and heterotopic thyroid tissue, cyst lined by respiratory epithelium/stratified squamous epi, thyroid follicles in cyst/duct wall. Mucus salivary-type glands can be found in cyst wall, secondary inflammation is common