Most commonly due to 2nd branchial remnants Repeat, from Nov 09 & Nov 06 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 1st 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 external opening along anterior border of sternocleidomastoid muscle and internal opening at the tonsillar fossa (The fistulous track passes in b/w internal & external carotid aeries) 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 cailage and present clinically as a firm mass or as a subcutaneous abscess. Rarely sinus may occur which open internally into pyrifon 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 bih although they may not become clinically evident until later in life. - Fistulas and sinus present at bih 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 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. About option 'a' - 'Cysts are more common than sinuses' - I am not sure what are more common. Sabiston write that in children ,fistulas are more common than sinuses which are more common than cysts. In adults cysts are more common.