True thymic hyperplasia associated with severe thymic cyst bleeding in a newborn: case report and review of the literature.

We report on a 5-week-old male infant with recurrent respiratory distress since birth and congenital thymic hyperplasia. Acute life-threatening thymic bleeding apparently from ruptured thymic cysts into the pleural spaces complicated the clinical situation. Thoracotomy and complete thymectomy were performed. Histologic examination revealed normal thymic architecture with cysts of different sizes and an increased thymic weight of 30 g. The combination of true thymic hyperplasia and cyst bleeding in a newborn has not been previously reported and will be discussed in relation to the available literature on respiratory distress due to thymic pathology in childhood.