True about branchial anomaly :
Branchiogenic Anomalies 

Branchial anomalies are remnants of the branchial apparatus present during the embryonic life.
Embryologically the structures of head and neck are derived from 5 pairs of branchial arches, their intervening clefts externally and pouches internally.
A tract of branchial origin may form a complete fistula, or one end may be obliterated to form an external or internal sinus, or both ends may resorb forming a cyst.
2nd branchial remnant are the most common
Ist branchial remnants are typically located in front or back of the ear or in the upper neck in the region of the mandible. Fistulas typically commence through the parotid gland and end in the external auditory canal.
2nd branchial cleft remnants cause fistulas/sinuses with an external opening along the anterior border of the sternocleidomastoid muscle and internal opening at the tonsillar fossa (The fistulous track passes in b/w internal & external carotid arteries)
3rd branchial cleft remnants usually do not have associated sinuses or fistulas and are located in the suprasternal notch or clavicular region. These most often contain cartilage and present clinically as a firm mass or as a subcutaneous abscess. Rarely sinus may occur which open internally into the pyriform sinus.
Branchiogenic anomalies occur with equal frequency on each side of the neck and 15% are bilateral.

Clinical presentation

By definition, all branchial remnants are present at the time of birth although they may not become clinically evident until later in life.
Fistulas and sinus present at birth whereas cysts usually appear in late childhood and adults.
Fistulas and sinuses usually discharge a mucoid or purulent material
The cysts are characteristically found anterior and deep to the upper third of the sternocleidomastoid (interior to the angle of mandible)
Sinuses and cysts are prone to become repeatedly infected producing cellulitis and abscess formation.

Treatment

Almost all branchial abnormalities should be excised early in life since repeated infection is common making resection more difficult.
Complete removal of the cyst and tract is necessary for a cure and preventing recurrence.
A series of two or sometimes three small transverse incisions in a "stepladder' fashion is preferred to a long oblique incision in the neck, which is cosmetically undesirable.