Congenital absence of the inferior vena cava, a rare cause of deep vein thrombosis in adolescent: Case report.

RATIONALE: Deep vein thrombosis (DVT) is rare in pediatric patients. Congenital inferior vena cava (IVC) anomalies are asymptomatic; however, these can cause DVT in younger patients rarely.

PATIENT CONCERNS: In this case, a 14-year-old male patient was referred to our hospital for lower abdominal pain.

DIAGNOSES: At the first hospital he visited, computed tomography revealed a thrombus in the veins of the abdomen and lower extremities; however, an accurate diagnosis could not be made because the thrombus was thought to be inconsistent with abdominal pain. Close examinations revealed swelling of the lower extremities and pain while walking. Contrast-enhanced computed tomography revealed the absence of IVC (AIVC), resulting in DVT at the external iliac, gonadal, inferior mesenteric, and collateral veins of the right pelvic cavity.

INTERVENTIONS: The patient received anticoagulation therapy.

OUTCOMES: At a follow-up 6 months later, his symptoms improved, and a thrombus was not found. AIVC could cause DVT.

LESSONS: DVT is rare in pediatric patients and is difficult to diagnose when the initial symptoms are vague. Conservative treatments are the most commonly used treatment; long-term follow-up is needed.