Abstract
Omental lymphangioma, a rare congenital benign lesion, represents a small proportion of abdominal lymphangiomas. Its diagnosis can be challenging, owing to its nonspecific symptoms and features that overlap with those of other cystic abdominal conditions. The report presents a case of an eight-year-old girl with progressive abdominal distension noted since the age of two years. Initially misattributed to constipation, the significantly worsening distension was later evaluated through imaging studies. Ultrasonography, magnetic resonance imaging (MRI), and contrast-enhanced computed tomography (CT) revealed a massive cystic lesion occupying the abdominal cavity. Although ultrasonography and MRI suggested a cystic mass, only contrast-enhanced CT could identify vessels within the septa as being branches of the gastroduodenal artery, thereby confirming the origin of the lesion to be in the greater omentum. The patient underwent laparoscopic-assisted omentectomy, with the aid of a SAND balloon catheter (Hakko Medical Industry, Tokyo, Japan), to prevent fluid leakage during the aspiration of 4.7 L of cystic fluid. Pathological examination confirmed the diagnosis of cystic lymphangioma. No recurrence has been observed over a follow-up period of more than five years. This case highlights the critical role of contrast-enhanced CT in localizing large abdominal lymphangiomas based on vascular anatomy and demonstrates its importance in guiding the surgical planning and management of this disease.