A Case of Giant Mediastinal Cyst Initially Detected and Diagnosed by Echocardiography

Mediastinal cysts are a group of benign mediastinal lesions, and their diagnoses are primarily depended on x‐ray and computed tomography. The development of ultrasound instruments and inspection techniques in recent years has led to the ability to use transthoracic echocardiography to clearly display structures surrounding the heart according to the dark fluid space (blood) of the atrium, ventricles, and large vessels as an acoustic window. This technique offers improved detection rates of mediastinal lesions. We report a case of a mediastinal cyst that was first detected and diagnosed on thoracic echocardiography examination and then confirmed by thoracoscopic surgery and pathological analysis.