According to Illingworth's theory, the inclusion of ectopic parotid epithelium in the upper deep cervical lymph nodes leads to the formation of
Branchial cyst.
Branchial fistula.
Cystic hygroma.
Thyroglossal fistula.
Branchial cyst
• It develops from persistence of precervical sinus, a small depression deep to the second arch that normally disappears during development.
• According to Illingworth's theory, inclusion of ectopic parotid epithelium in the upper deep cervical lymph nodes leads to branchial cyst formation.
• Though congenital, it often manifests itself between 20-25 yrs. of age, or even later. Presents as a painless swelling in the upper and lateral part of the neck.
• It shows a tendency of recurrent infection due to presence of lymphoid tissue in its wall. In that case it becomes painful.
• Cholesterol crystals can be demonstrated in the aspirated fluid from a branchial cyst.