An unusual cause of a toddler with a big belly, abdominal lymphatic malformation case report

: Abdominal pain is one of the most common complaints seen in the pediatric emergency department (PED). Because of the broad range of potential diagnoses, it can pose challenges in the diagnostic evaluation and treatment in the young child. A 3-year-old previously healthy girl presented to our PED with abdominal pain, abdominal distention, poor appetite, and recent weight gain. Physical examination was notable for a significantly distended taut abdomen in an otherwise well appearing child with normal vital signs. Initial evaluation yielded anemia, elevated inflammatory markers, and an abdominal ultrasound (US) showing a large amount of complex intra-abdominal ascites without definite intra-peritoneal mass. Pediatric surgery, pediatric gastroenterology, and pediatric oncology were consulted. A magnetic resonance imaging (MRI) of the abdomen was performed and revealed a large amount of intraperitoneal fluid with a component of internal complexity and no suspicious enhancement to suggest overt malignant process. She was ultimately diagnosed with a large congenital omental cyst that required resection and omentectomy. Pathology was consistent with a macrocystic lymphatic malformation. Lymphatic malformations are uncommon pediatric lesions, accounting for only 5% of benign tumors in childhood. Common locations include the neck, axillae, and rarely involve the gastrointestinal tract. Clinical presentation varies depending on the size and location of the tumor. Many present later in life due to their diagnostic challenges.