Thymus is a lymphoid organ that develops from the 3rd and 4th pharyngeal pouches. While the pathogenesis of cervical thymus cyst is still unclear, there are two main mechanisms by which this lesion occurs: # Congenital: During the fetal development, the thymus forms from the third branchial pouch which descends lateral to the mediastinum toward the thyroid gland. A remnant of this<unk>  tissue can persist during its descent through the thymopharyngeal duct, and later on become the cause of the lesion. This mechanism has been better supported by the authorities. # Acquired: The<unk>  tissue, mainly the Hassall corpuscles and epithelium reticulum, progressively degenerates and ascends upward to cause the lesion.
Cervical thymic cyst
Cervical lymphadenopathy
Thoracic endometriosis
Ectopic thymus
Laryngeal cyst
Inguinal lymphadenopathy
Mycobacterial cervical lymphadenitis
ALPSA lesion