branchial cleft cyst
description
abnormal persistence of remnants of the branchial apparatus results in cysts, sinuses and fistulas. only cysts will be amenable to prenatal diagnosis. cysts are spherical structures lying along the track of a branchial pouch or cleft, having no communication with the surface skin or pharynx. nearly all cystic remnants of the branchial apparatus are derived from the second pouch or cleft. they may be found anywhere along the pathway of a second cleft fistula and usually present as a swelling in the upper neck along the anterior edge of sternocleidomastoid muscle. these anomalies are bilateral in one third of cases. unilateral cysts are generally right sided. no sex predilection has been reported.
diagnosis
branchial cleft cysts are rarely diagnosed in fetal life, and more often present in late childhood or adulthood. transverse views through the neck will reveal a uniform mass in the upper anterior neck, along the medial border of sternocleidomastoid muscle.
differential diagnosis
teratoma has a complex echo pattern, with solid and cystic components. calcification may be present in both haemangioma and teratoma, however gross calcification is generally restricted to teratoma, and fine scattered calcification to haemangioma. a haemangioma is a cystic, solid or mixed mass. occasionally it will be accompanied by multiple internal homogeneous echogenic reflections, representing calcified areas. these are small and widely scattered, unlike the gross calcification of a teratoma. cystic areas may be pulsatile. doppler velocimetry should demonstrate low-resistance blood flow through the cystic areas. a goitre will present as a mainly solid mass, with echolucent areas. lymphangiomas are often multiloculated, with linear septations of variable thickness. solid portions are found within and between the cysts.
sonographic features
cystic neck mass, along the medial border of sternocleidomastoid muscle, usually in the upper neck.
associated syndromes
- none
references
hoyme he in: human malformations and related anomalies oxford university press, pp417-8