<prompt> Cystic compressible, translucent swelling in the posterior triangle of neck:-Cystic hygromaBranchial cystThyroglossal cystDermoid cyst  <response>: Cystic compressible, translucent swelling in the posterior triangle of neck is cystic hygroma. CYSTIC HYGROMA Multiloculated cystic spacesQlined by endothelial cells Due to sequestration of a poion of jugular lymph sac from the lymphatic systemQ. Cysts are filled with clear lymph and are lined by endotheliumQ. Turners syndromeis associated with cystic hygromaQ. Most cystic hygromas involve the lymphatic jugular sacs MC site: Posterior neck regionQPosterior triangleQ Other common sites: Axilla, mediastinum, inguinal retroperitoneal regionsQ CLINICAL FEATURES Usually present as soft cystic masses that disto the surrounding anatomy, can result in acute airway obstruction. Usually manifests in the neonates or in early infancyQ50 present at bih. Characteristic feature: Brilliantly translucentQ 