A Thornwaldt cyst (also spelled as a Tornwaldt cyst or Thornwald cyst) is a common incidental benign midline nasopharyngeal mucosal cyst.
Thornwaldt’s cysts are classified as crusting and cystic 8. They form as a result of retraction of the notochord where it contacts with the endoderm of the primitive pharynx.
This is believed to happen at about the 10th week of embryonic development. Closure at the orifice results in so called cystic type, while crusts adhering to the orifice without closing result in crust type 8. The cyst is lined by respiratory epithelium and accumulates with fluid with variable proteinaceous content, inflammation can occur due to obstruction.It is named after Gustav Ludwig Thornwaldt, German physician, 1843-1910