Desmoid tumors are rare soft tissue tumors arising from the fascia or from musculoaponeurotic structures. They are commonly seen in the extremities, but are rarely found in the thorax. Thoracic desmoid tumors commonly arise from the chest wall and rarely in the thoracic cavity. Imaging diagnosis of an intrathoracic desmoid tumor is difficult because there are no specific imaging findings for a desmoid tumor that can be differentiated from the various tumors of the chest wall, including a solitary fibrous tumor of the pleura. All desmoid tumor cells show negative immunohistochemical staining for CD34 in pathological specimen, a feature that makes it possible to differentiate a desmoid tumor from a solitary fibrous tumor of the pleura. Desmoid tumors are locally aggressive and the rate of local recurrence is very high. Consequently, wide radical resection is required and a preoperative accurate diagnosis of desmoid tumors is warranted. We describe the radiological findings of various imaging studies for an intrathoracic desmoid tumor. Our findings should facilitate a proper diagnosis of desmoid tumors.