This is a rare neoplasm believed to arise from ectopic or aberrant thymic tissue in either lung or pleura, with histologic features resembling those of thymomas occurring in the thymus gland. The clinical manifestations are nonspecific including cough, chest pain, and fever. Tumors located near the pleura may be associated with effusions. Rare cases associated with myasthenia gravis have been reported. Radiologic findings refer to the presence of a mass lesion and are said to be nonspecific. An important consideration when considering a tumor solely on basis of chest radiograph and/or gallium67 studies is the scanning of any possible extension of a mediastinal thymoma into the lung tissue, mimicking a primary lung tumor. In such instances, CT scanning can, in some cases, correctly identify a connecting pedicle, tracing the tumor back into the mediastinum.