- M/C congenital cause of neck masses.
- M/C second arch branchial cysts (90% cases)
Bailey classification of second branchial cleft cysts:
- Type I (M/superficial): Anterior margin of sternocleidomastoid muscle, deep to platysma muscle
- Type II (M/C): Along anterior margin of sternocleidomastoid muscle, lateral to carotid space and posterior to submandibular gland (classic location)
- Type III: Extends medially b/w carotid bifurcation and lateral wall of pharynx
- Type IV: Lies in pharyngeal mucosal space; lined with columnar epithelium
Incomplete involution of branchial cleft structures between the second and sixth–seventh weeks of fetal life.
Although the masses are congenital, they are usually identified only in the second to fourth decades of life, when they become enlarged secondary to infection or rupture.
- Unilateral, slow-growing, fluctuant soft-tissue swelling that typically appears in the lateral aspect of the neck.
- Fluid-filled cyst outlining its size and anatomic relationships
- Characteristic thick wall of a branchial cyst
- Carotid body tumour
- Cystic hygroma
- Ectopic thyroid/salivary tissue
- Vascular neoplasm/malformation