Branchial cyst is found in

A branchial cyst probably develops from the vestigial remnants of the second branchial cleft, is usually lined by squamous epithelium, and contains thick, turbid fluid full of cholesterol crystals. The cyst usually presents in the upper neck in early or middle adulthood and is found at the junction of the upper third and middle third of the sternomastoid muscle at its anterior border. It is a fluctuant swelling that may transilluminate and is often soft in its early stages so that it may be difficult to palpate. If the cyst becomes infected it becomes erythematous and tender and, on occasions, it may be difficult to differentiate from a tuberculous abscess. Ultrasound and fine-needle aspiration both aid diagnosis and treatment is by complete excision, which is best undeaken when the lesion is quiescent. Although the anterior aspect of the cyst is easy to dissect, it may pass backwards and upwards through the bifurcation of the common carotid Bailey & Love ,25th,727.