Sonography in the diagnosis of branchial cysts.

Four cases of surgically proven branchial cysts were examined sonographically. These lesions demonstrate cystic sonographic characteristics but may also contain low-level echoes secondary to superimposed infection. Their usual location anterior to the carotid sheath and sternocleidomastoid muscle and separate from the thyroid gland can be explained by their embryologic derivation. While it may be difficult in some cases to differentiate branchial cysts from abscess or an anechoic solid mass such as lymphadenopathy, careful attention to their typical location and sonographic characteristics as well as the history will aid in the correct preoperative diagnosis of branchial cysts.