Solitary Fibrous Tumors of the Pleura: A Poorly Defined Malignancy Profile

Background. The aim of this study was to evaluate the clinical characteristics and factors that influence the long-term outcomes of solitary fibrous tumors of the pleura. Methods. We conducted a retrospective study in 2 centers and reviewed 80 patients who underwent surgery between May 1984 and April 2011. Results. Of the 80 patients (29 male; median age, 60 years [33 to 85 years]), 47 were symptomatic (59%). The tumors originated from the visceral pleura in 62 cases (79%) and from the parietal pleura in 18 cases (22%). The tumors were pedunculated in 66 cases (83%) and sessile in 20 cases (17%). Surgical resection with histologically free margins was accomplished in 76 of 79 patients (93%). The tumors were classified as benign in 51 cases (65%) and as malignant in 28 (35%). The factors that were significantly associated with malignant tumors were the presence of symptoms (P = 0.03), a mean diameter 10 cm or greater (P = 0.0004), fibrous adherences (P = 0.003), pleural effusion (P = 0.003), and a Ki67 10% or greater (P = 0.003). The median follow-up was 69 months (range, 1 to 315). Local recurrence occurred in 3 cases. The overall 5- and 10-year survival rates were 90% and 86%, respectively, and the mean survival time was 255 +/- 15 months. There were no differences between the benign and malignant tumors. Conclusions. The recurrence rates are low after surgeries for both benign and malignant solitary fibrous tumors of the pleura. However, the factors that are predictive of recurrence have yet to be specified and require additional immunohistochemical and genetic investigations. (C) 2015 by The Society of Thoracic Surgeons