Thrombosed cavernous hemangioma of the anterior mediastinum in a five-year-old boy: CT and MR appearances.

We report a case of histologically proven mediastinal hemangioma with clot formation. Although contrast-enhanced CT demonstrated the multilocular nature by enhancement of the septum, each locular space was not enhanced by the contrast medium. On both T1- and T2- weighted MR images, the signal intensity of the mass was very high and unhomogenous with low intensity septa. Clot formation in the cavernous lumen can be a reason for the lack of vascularity on contrast-enhanced CT. MRI is useful in diagnosing thrombosed hemangioma because of its high sensitivity to methemoglobin formation.