Musculoskeletal pain is a common symptom among active adolescent in the emergency department. The etiologic list is broad and range from benign to potential life-threatening conditions. Deep vein thrombosis is a rare cause of lower extremity pain in children. We report an adolescent who presented with lower extremity pain and a careful evaluation revealed an abdominal mass. Further investigation determined the presence of iliofemoral deep venous thrombosis and absence of the inferior vena cava. Absence of inferior vena cava is an uncommon congenital malformation in children and is a possible risk factor for the development of venous thrombosis. This case emphasizes the importance of thorough physical examination in children with nonspecific symptoms. If venous thrombosis is identified, especially in patients without any apparent risk factors, congenital anomalies of inferior vena cava should be considered. The pertinent literature is reviewed.
