Primary Small Intestine Lymphatic Dilation Syndrome: A Case Report

Background Primary intestinal lymphatic dilation (PIL) is a rare disorder that is characterized by abnormal intestinal lymphatic drainage; however, its exact etiology and pathogenesis are yet to be fully elucidated. PIL primarily originates from impaired lymphatic return in the small intestine owing to multiple factors, and leads to increased lymphatic vessel pressure with consequent lymph fluid leakage, malabsorption, and protein loss. The clinical manifestations typically include hypoproteinemia, lymphopenia, diarrhea, and ascites. Case presentation: A 14-year-old female patient was admitted to the hospital because of exertional dyspnea for half a month, nausea and vomiting accompanied by abdominal distension and pain for 10 days, and bilateral lower limb swelling for 3 days. Examination revealed a large amount of fluid accumulation in the abdominal and pelvic cavities, pleural effusion, hypoproteinemia, hypogammaglobulinemia, electrolyte imbalance, decreased lymphocyte count, and a positive result on the chylous test of pleural and abdominal effusions. The CT scan revealed intestinal obstruction, intestinal dilation, and enlargement of the mesenteric lymph nodes. The PET-CT examination ruled out lymphoma. Gastroscopy revealed that the ileal mucosa was edematous, with diffuse patchy changes and granular protrusions on the surface. An ileal biopsy showed dilated lymphatic vessels within the lamina propria, accompanied by infiltration of inflammatory cells. Based on the patient's clinical symptoms and results of the examinations, she was diagnosed with small intestinal lymphatic dilation. After conservative treatment, including albumin supplementation, electrolyte imbalance correction, and nutritional support, the patient's symptoms were alleviated and she was discharged. Conclusion The diagnosis of pediatric small intestinal lymphangiectasia requires a comprehensive consideration of clinical symptoms, laboratory tests, imaging examinations, and endoscopic pathological biopsy results. Pathological histology is key to confirming a diagnosis. The early implementation of targeted conservative treatment can effectively improve patient prognosis.