Ultrasound diagnosis of thymic hemorrhage in an infant with late-onset hemorrhagic disease.

Thymic hemorrhage related to coagulopathy by vitamin K deficiency is a rare condition. We report a case in a 4-week-old boy presenting with acute onset of respiratory distress and anemia. Ultrasound examination of a compressive anterior mediastinal mass established the diagnosis of thymic hemorrhage and allowed us to follow resolution under medical treatment.