-Most patients are between 45 and 65 years, without significant sex difference. Most (up to 3/4) arise from visceral pleura. Pedunculation is present in about 50%. On microscopic examination, the lesion consists of spindle-shaped cells seperated by collagen. It exists in benign and malignant forms; 14% to 30% are malignant. In about half the patients the tumor is asymptomatic and detected incidently on chest radiograph. The most common symptoms are cough, chest pain, and dyspnea. Hypertrophic osteoarthropathy is reported in 4% to 12% of patients. Symptomatic hypoglycemia is seen in up to 6% of patients.

-On chest radiograph, the usual finding is a slow-growing, oval, often lobulated, homogeneous mass in contact with pleura. The lesions vary in size from less than 1 cm to 30 cm but usually large when initially detected. Tumors on pedicles may change in shape and position on different occasions and in different postures. On CT the lesions are usually well defined, based on a pleural surface. On contrast-enhanced CT, inhomogeneous enhancement is a frequent feature due to mixed areas of hemorrhage, cyst, myxoid change and soft tissue elements. Calcification is infrequently present. On T1-weighted MR images, tumors showed low signal intensity. Tumors had heterogeneous signal intensity on T2-weighted images. After IV administration of gadolinium, soft tissue elements of tumors are well enhanced.