Abstract:Objective: To identify CT characteristics of primary pulmonary malignant fibrous histiocytoma(MFH). Materials and Methods: CT images and clinical data of 15 patients with primary pulmonary MFH proved pathologically were reviewed and analyzed retrospectively. Results: Among 15 patients, MFH appeared as peripheral lesions in 12 cases, located in left lobe 7 cases, right lobe 5 cases and central 3 cases. A total of 20 lesions were identified, in which 12 had single lesion and 3 had mutiple lesions, with mean a diameter of 8.5 cm and ranged between 3.5~15.4 cm, including 12 round-shaped and 8 mild lobulated lesions. Among all the 20 lesions, 14 were well-defined and the others had unclear border, while 5 masses were homogenous in density and the other 15 were inhomogenous with necrosis, cysts, bleeding or calcification. Twelve patients underwent enhanced CT, 17 lesions had various degress of enhancement in arterial phase and venous phase. Six lesions involved pleura and chest wall(among which 3 involved ribs), 1 involved pulmonary artery, 1 involved pulmonary vein, 2 involved pericardium, as well as 5 metastasis on pulmonary hilar or mediastinal lymph node, 4 distant metastasis. Conclusion: Primary pulmonary MFHs have some specific CT manifestations which are helpful to the diagnosis, but final diagnosis depends on the cytopathology and immunohistochemistry.