Life-threatening and Rapidly Growing Teratoma in the Anterior Mediastinum

This report describes the case of a 23-year-old man with a mediastinal teratoma. Five months before admission, a chest radiograph during a routine health checkup was normal. Four months before admission, the patient developed sudden onset of mild right-sided chest pain. He gradually developed dyspnea and was admitted to our hospital. Computed tomography revealed a giant tumor that was markedly compressing the right atrium. Urgent surgery was performed, and a ruptured, benign mature teratoma was diagnosed. Mature mediastinal teratomas are benign tumors, but they can rupture and have the potential to grow rapidly, potentially leading to life-threatening complications.