Rapid progression of thymoma in a 3-year-old-girl

Abstract

Thymoma is an uncommon neoplasm that derived from thymic epithelial cells. Clinically, it is slow-growing and most patients are over 40 years old. Thymoma corresponds to 30% of anterior mediastinal tumors in adults but <1% in pediatric patients. However, thymoma in pediatric group is considered to be highly aggressive. We report a case of invasive thymoma in a 3-year-old girl, presented as respiratory distress with massive pleural effusion. She developed a superior vena cava syndrome soon after admission. A subsequent computed tomography demonstrated a large mediastinal mass with compression of great vessels. Due to the rare occurrence of thymoma at such a young age, an accurate diagnosis was made only after an open biopsy had been performed. The patient underwent a near-complete resection of the mass as well as adjuvant chemotherapy. She has remained well at the 6-year follow-up.