Although rare, thymoma is the most frequent type of malignancy in the anterior mediastinum. On most occasions, radiological diagnosis is easy, owing to current imaging studies like computerized tomography. Additionally, the radiological diagnosis of thymoma can be differentiated easily from malignant pleural mesothelioma in most cases. However, thymoma's differentiation from lymphoma, thymic hyperplasia, or thymic remnants sometimes may pose diagnostic challenges. Here, we report a case of advanced thymoma mimicking malignant pleural mesothelioma, with circumferential encasement of the lung. A brief review of the literature with special reference to radiological imaging on thymoma also is presented.