Malignant solitary fibrous tumor (SFT) of the thorax is a rare tumor of fibroblastic/ mesenchymal origin. Most SFTs arises in the visceral pleura are usually asymptomatic and discovered incidentally but as many as 10% of them behave aggressively. Larger tumors can present with symptoms of cough and dyspnea as in this case. Histologically, most SFTs are well-circumscribed with uniform spindle cells with varying cellularity and staghorn vessels. The more aggressive ones shows increased mitotic activity, hypercellularity and couagulative necrosis. In general, risk stratification are preferred over anatomical staging for these aggressive ones. The risk stratification system is based on patient’s age, tumor size, and mitosis and tumor necrosis ( please see references below). This solitary fibrous tumor shows mainly spindle cell and focally epithelioid morphology with high mitotic rate up to (14 mitosis/10hpf) and numerous pleomorphic and large multinucleated giant cells.