A Rare Case of a Large Intra-Abdominal Lymphatic-Venous Malformation in a Young Woman Presenting to the Emergency Room with Abdominal Pain

<b>Background and Clinical Significance</b>: Lymphatic-venous malformations (LVMs) are uncommon congenital vascular anomalies with low blood flow, consisting of atypical connections between lymphatic and venous vessels. They may develop in different body regions, with a predilection for lymphatic-rich areas. Fewer than 5% of LVMs are located intra-abdominally, typically arising from the mesentery, retroperitoneum, or greater omentum. Patients with intra-abdominal LVMs may be asymptomatic, but they can also present with symptoms such as acute abdominal pain, chronic discomfort, palpable masses, or progressive abdominal distension. <b>Case Presentation</b>: This case describes a 24-year-old female who presented to our emergency department with progressive abdominal distension, nausea, and vomiting. <b>Conclusions</b>: The diagnosis of LVMs can be challenging and requires a combination of imaging techniques, including ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI), along with histological confirmation.