Objective: The purpose of this study was to investigate the effects of diagnostic and surgical developments in the complete resection of the mediastinal masses. Methods: Of 313 patients, 236 underwent therapeutic or diagnostic complete resections. We analyzed age, gender, diagnostic interventions, neoadjuvant treatment, type of surgical intervention (sternotomy, video-assisted thoracic surgery [VATS], thoracotomy), pathology, duration of hospital stay, complications, mortality, and associated diseases. Patients were divided into two groups according to the period of operation: group A included patients who were operated on between January 2002 and January 2007; group B included patients who were operated on between January 2007 and January 2012. Results: Resection with VATS increased significantly after 2007, from 17.7 to 35 % ( p = 0.03). The rate of complications increased after 2007 ( p = 0.03), which was apparent in non-VATS patients ( p = 0.03). The use of magnetic resonance imaging (MRI) decreased from 29 to 15.5 % ( p = 0.02) and positron emission tomography (PET)-computed tomography (CT) use increased from 1.6 to 25.2 % ( p < 0.001). Conclusions: We identified a paradigm shift in mediastinal mass surgery. PET-CT became a more preferred diagnostic method and MRI became less preferred. The rate of VATS resection doubled and sternotomy decreased. Complication rates increased in non-VATS due to an increase in extended resections. [ABSTRACT FROM AUTHOR]