Ans. c (A Cystic lesion containing blood filled spaces) (Ref. Bailey and Love 25th/pg. 700)CYSTIC HYGROMA (CAVERNOUS LYMPHANGIOMA)# Sequestration of a portion of the jugular lymph sac from the lymphatic system accounts for the appearance of these swellings.# Cystic hygroma usually manifests itself in the neonate or in early infancy, and occasionally may be present at birth and be so large as to obstruct labour.# Swelling usually occurs in the lower third of the neck and as it enlarges it passes up towards the ear.# Often the posterior triangle of the neck is mainly involved.# Brilliantly translucent.# The cheek, axilla, groin and mediastinum are other, although less frequent, sites for a cystic hygroma.# Rx:- Spontaneous regression may occur.- Definitive treatment is excision of the entire cyst at an early stage.- A preliminary injection of sclerosing agents is not advisable.- Recurrence is common with percutaneous PICIBANIL therapy.BRANCHIAL CYST# The first cleft persists as the external auditory meatus, but the second, third and fourth normally disappear.# A branchial cyst 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 branchial cyst usually presents in the upper neck in early or middle adulthood.# It is found at the junction of the upper third and middle third of the sternomastoid muscle at its anterior border.# Ultrasound and fine needle aspiration both aid with diagnosis, and treatment is by complete excision.# Rx- Although the anterior aspect of the cyst is easy to dissect, it may pass backwards and upwards through the fork of the common carotid artery as far as the pharyngeal constrictors.- It passes superficial to the hypoglossal and glossopharyngeal nerves but deep to the posterior belly of the diagastric.- The hypoglossal and spinal accessory nerve are encountered in the operative field and must be positively identified to avoid damage.BRANCHIAL FISTULA# They are thought to represent a persistent second branchial cleft.# A branchial fistula may be unilateral or bilateral.# Their external orifice is nearly always situated in the lower third of the neck near the anterior border of the sternocleidomastoid, whilst the internal orifice is located on the anterior aspect of the posterior faucial pillar just behind the tonsil.# However, the internal aspect of the tract may well end blindly at or close to the lateral pharyngeal wall, constituting a sinus rather than a fistula.# The tract is lined by ciliated columnar epithelium and as such there may be a small amount of recurrent mucous or mucopurulent discharge on to the neck. Rx. Complete surgical removal.