Background: Ancient schwannoma is a rare variant of schwannoma, histologically showing atypical features that may result in erroneous diagnosis of a malignant tumor. There are only few reported cases in literature. Case Description: We report a case of a 34-year-old man who was found to have giant mediastinal tumor. He underwent thoracotomy to remove the mass, which was proven to be ancient schwannoma on histopathology. Conclusions: Clinical and radiological findings are important aids for further consideration of surgical removal of these potentially respectable tumors with good outcome.