RESUMEN
An 11-yr-old boy was admitted to the hospital with gradually aggravating acute abdominal pain along with nausea, vomiting and constipation for 5 days. The pain started after blunt trauma on the superior abdomen. He had normal laboratory tests and abdominal examination, but his chest radiograph showed infiltration in the right lung and an abnormal mass on the left diaphragm. Further investigation like computed tomography (CT) and magnetic resonance MR angiography, revealed an abnormal para-aotic mass located a mass located para-aortic above posterior to the left diaphragm with a well-defined margin. The abnormal mass was finally confirmed to be a hematoma with exploratory thoracotomy. The rarity of this kind of presentation is discussed for making an early and correct diagnosis.