Extramedullary hematopoiesis as a differential diagnosis of mediastinal masses

Intrathoracic extramedullary hematopoiesis is a rare disease in the differe ntial diagnosis of mediastinal masses. It is suggested that asymptomatic ma sses should not be treated. A correct diagnosis can thus help to avoid an o peration. The aim of this case report is to draw attention to this phenomen on as a cause of mediastinal masses and to provide information about diagno stic facilities available. We report the case of a 53-year-old male patient with hereditary spherocytosis as well as the case of a 59-year-old male pa tient with pyruvate kinase deficiency who showed intrathoracic paravertebra l masses, that were identified in the first case by video-assisted thoracos copic intervention (VATS) and in the second case by thoracotomy as a region of extramedullary hematopoiesis.