A<unk> , also called thymopharyngeal duct cyst, is a fluid-filled mass that occurs when the thymopharyngeal duct, an embryonic structure connecting the nascent thymus with the embryonic pharynx, fails to close and disappear. A<unk>  cyst is typically a solitary mass on one side of the neck, and is usually found near the carotid sheath. Some<unk> s may extend into the mediastinum. It is usually asymptomatic. The diagnostic process includes differentiating between other causes of neck masses in infants and children, including branchial cleft cysts and cystic hygromas. The treatment is surgical excision. On histologic examination, the wall of the cyst includes<unk>  tissue, and may include parathyroid gland tissue because of the parathyroid gland's common embryonic origin with the thymus gland in the third pharyngeal pouch. Fewer than 100 cases of<unk> s have been reported in the medical literature.
Cervical thymic cyst
Cervical lymphadenopathy
Thoracic endometriosis
Ectopic thymus
Laryngeal cyst
Inguinal lymphadenopathy
Mycobacterial cervical lymphadenitis
ALPSA lesion