RT Book, Section A1 Shah, Ashish A1 Sobolewski, Brad A1 Mittiga, Matthew R. A2 Knoop, Kevin J. A2 Stack, Lawrence B. A2 Storrow, Alan B. A2 Thurman, R. Jason SR Print(0) ID 1181044535 T1 Cystic Hygroma T2 The Atlas of Emergency Medicine, 5e YR 2021 FD 2021 PB McGraw-Hill PP New York, NY SN 9781260134940 LK accessemergencymedicine.mhmedical.com/content.aspx?aid=1181044535 RD 2024/10/10 AB Cystic hygromas are congenital lymphatic malformations found most commonly in the neck in infants and children less than 2 years of age. They present as nontender, compressible, unilocular, or multilocular masses with thin, transparent walls filled with straw-colored fluid. Unlike hemangiomas, these lesions rarely undergo spontaneous involution. The vast majority tend to grow and infiltrate adjacent structures. In cases where the tongue is involved, they may lead to upper airway obstruction. The differential diagnosis includes branchial arch remnants, thyroglossal duct cysts, cystic teratomas, cervical lymphadenopathy, and other primary neoplastic diseases.