<s>[INST] context: Cystic hygroma usually present in the neonate or in early infancy, and occasionally may present at bih and be so large as to obstruct labour. The cysts are filled with clear lymph and lined by a single layer of epithelium with a mosaic appearance. Swelling usually occurs in the neck and may involve the parotid, submandibular, tongue and floor of mouth areas. The swelling may be bilateral and is soft and paially compressible, visibly increasing in size when the child coughs or cries. The characteristic that distinguishes it from all other neck swellings is that it is brilliantly translucent. The cheek, axilla, groin and mediastinum are other less frequent sites for a cystic hygroma. The behaviour of cystic hygromas during infancy is unpredictable. Sometimes the cyst expands rapidly and occasionally respiratory difficulty ensues, requiring immediate aspiration andeven occasionally a tracheostomy. The cyst may become infected. Definitive treatment is complete excision of the cyst at an early stage. Injection of a sclerosing agent, for example picibanil (OK-432), may reduce the size of the cyst; however, they are commonly multicystic and if the injection is extracystic subsequent surgery may be more difficult Bailey & Love ,25th,729. [/INST] question: Best treatment of cystic hygroma is ? | options: A: Radiotherapy B: Sclerotherapy C: Surgical excision D: Chemotherapy | answer: C </s>