Resection of an intrapulmonary solitary fibrous tumor in the center of the middle lobe: a case report.

A 75-year-old female patient was referred to our hospital due to an abnormal shadow detected by chest X-ray. Computed tomography scans revealed a well-circumscribed nodule measuring 28 mm between B4 and B5 in the right middle lobe. Because the tumor was in the center of right middle lobe, a middle lobe resection was performed. The tumor was located within the lung and there were no obvious pleural surface changes. Postoperative histological findings showed 34-mm firm and round tumor, and well circumscribed without involving the visceral pleura. The pathologic examination revealed proliferating spindle-shaped cells with a random fascicular arrangement with continuity to the pulmonary interstitium. Not much cellular atypia was observed. Immunohistochemical staining indicated that the tumor was positive for STAT6, CD34. The final diagnosis was an intrapulmonary benign solitary fibrous tumor (SFT). Even benign intrapulmonary SFTs that have been completely resected may later become malignant and recur, and careful follow-up is necessary.