Abstract
Anterior mediastinal masses are generally asymptomatic until they grow and compress surrounding structures. Chest X-rays only suggest a mediastinal abnormality and contrast-enhanced CT scan and MRI are necessary for a better definition of the lesion. The classification of the anterior mediastinal masses is based on their etiology and it is sometimes a challenge to have an accurate differential diagnosis based only on radiological examinations: therefore, only the histopathological examination makes the correct diagnosis. Surgeons generally agree that symptomatic masses or those with progressive growth should undergo surgical resection. We report a case of an accidental finding of an organized thymic hematoma in a 46-year-old female. At first totally asymptomatic, the hematoma was misdiagnosed for a thymic cyst and resected when it increased in size and compressed surrounding mediastinal structures. A detailed anamnesis highlighted a minor thoracic trauma which turned out to be the cause. Retrosternal hematoma generally grows several months after trauma and initial stabilization; therefore, it is mandatory to include an organized hematoma in the differential diagnosis of the retrosternal neoformations.