Objective To describe a case of giant asymptomatic neurilemmoma of mediastinum. Methods The clinical, radiographic and pathological characteristics of a patient admitted to Changhai Hospital Affiliated to Second MilitaryMedical University in May 2009 presenting with large shadow on chest radiograph was analyzed, and related literature was reviewed. Results Radiographic examination revealed a large mass occupying the right thoracic cavity. Then the pathological issue was obtained bypercutaneous CT-guided needle biopsy. Neurilemmoma was proved by pathological study. Conclusions The low morbidity of giant neurilemmoma of mediastinum, with most of the cases remaining asymptomatic, is prone to misdiagnosis. The large mediastinal mass in the thoracic cavity increases the risk of thoracotomy. It can bepathologically diagnosed through percutaneous image-guided needle biopsy or surgical biopsy.