Solitary fibrous tumors of pleura and lung: report of twelve cases

Purpose: Solitary fibrous tumors (SFTs) of pleura and lung are rare primary tumors that arise from the submesothelial tissue and usually show a benign clinical course. Immuno-histochemical analysis is used to make the diagnosis. We have reviewed our experience to obtain a better understanding of this disease. Methods: In this study, we reviewed 12 patients who had undergone a surgical resection for treatment of benign solitary fibrous tumors (SFTs) of pleura and lung during the period from 2006 to 2012. Results: Following excision, the most essential characteristic on histopathology was nonatypical spindle-shaped tumor cells on a collagenous background. Keloid-type collagen, hypocellular and hypercellular areas could be observed in all the cases. On immuno-histochemical analysis, we found that mesenchymal markers such as CD34, bcl-2 and vimentin were positive, and S-100 protein and desmin were negative. In addition, Ki-67 was positive in approximately 5% of the tumor cells, but C-kit protein was not detected. If the result for CD34 was negative, expression of bcl-2 was positive. Complete resection was performed through thoracotomy, including 8 cases that involved video-assisted thoracic surgery (VATS). The postoperative courses were uneventful, and there was no recurrence during 3-65 (mean 25) months of follow-up. Conclusions: Complete resection of SFTs is usually curative. Morphological and pathological features are important in distinguishing them from other tumors and in predicting clinical behaviour.