This is a case report on a 14 year child with a benign mediastinum lipoblastoma examined at the University Hospital "Dr. José E. González", in Monterrey, Nuevo León. This is an infrequent pathology and little has been published especially dealing with patients at this age and the site where it was found. This is a benign tumor which requires complete resection. The patient was submitted to an anterolateral bilateral thoracotomy which allowed for the complete resection of the tumor. It weighed 3.1 kilograms and measured 26 x 21 cm. The patient evolved satisfactorily.