We resected a fist-sized, solitary fibrous tumor of the pleura (SFTP) with a minute malignant component, following percutaneous embolization of its feeding artery. The tumor had macroscopic characteristics of a benign SFTP, and most parts of it were microscopically benign. However, further careful pathological examination revealed a minute malignant component in its periphery. We report this case to show that large and mostly benign SFTPs may contain malignant components, which can be overlooked. Thus, large SFTPs should be resected in consideration of this possibility.