RESUMEN
BACKGROUNDS: Manifestation of cystic hygroma in adulthood is very rare. The rarity of cystic hygroma in adults has caused problems in its diagnosis and management and few studies have reported cystic hygroma in adults. CASE PRESENTATION: In this study, we reported a rare case with cervical cystic hygroma in adults. We report a 20-year-old Iranian male (Iranian ethnicity) with a diagnosis of right-side neck cystic hygroma and discuss the presentation, diagnosis, and clinical, radiological, and operative aspects of it. CONCLUSION: Cystic hygromas are a rare occurrence in adults. They are typically asymptomatic, rarely complicated, and can be mistaken for a cystic neck mass. This study showed that in our case, surgical resection may be a safe and effective treatment for cystic hygroma, with minimal risk of complications during the procedure.