Type B3 Thymoma in a Twelve-Year-Old Girl

Thymic epithelial tumors consist of thymomas, thymic carcinoids, and thymic carcinomas. Most cases occur over the age of 20 years, and 70% of cases in patients over 40 years of age. Thymomas are extremely uncommon in children, accounting for less than 1% of childhood mediastinal tumours compared with 30% in adults and, because of their rarity, may be difficult to diagnose. In this paper, we present a 12-year-old girl who presented with symptoms of pneumonia such as cough, fever and chest pain. Her chest x-ray showed expansion of the mediastinum and opacity in the right hemithorax. An anterior mediastinal mass was determined by chest computed tomography. Histological and immunochemical examination of the surgically excised mass showed type B3 thymoma. The case is presented for its rarity in children.