title: Prognostic factors in solitary fibrous tumors of the pleura.
abstract: BACKGROUND
  Solitary fibrous tumors of the pleura (SFTP) are rare neoplasms originating from submesothelial mesenchymal cells with fibroblastic differentiation. The clinical behavior of SFTPs is mostly benign; however, up to 20% of patients develop local recurrence and/or distant metastasis. Although different risk-stratification models have been described, definitive criteria to predict a malignant clinical course of SFTP are still lacking.
  
  
  METHODS
  In a retrospective analysis at a single-institution, 25 patients with histologically proven SFTP were identified. Clinicopathologic and survival data were collected and pathologic sections reviewed. Different markers and risk-stratification models were correlated with disease- and overall-free survival by Kaplan-Meier analysis.
  
  
  RESULTS
  Of 25 SFTP, 8 tumors (32%) were classified as malignant according to the World Health Organization criteria. Three patients (12%) developed recurrence. Cohort median follow-up was 28 mo, and median overall survival was 160 mo. Comparison of proliferation markers showed higher mitosis count per high-power field and MIB-1 labeling index (MIB) in malignant compared with nonmalignant SFTP. MIB was identified as a predictor for disease-free survival. Applying the previously reported classifications to categorize SFTP according to the probability to show malignant behavior, significant differences in disease-free survival were also present in our cohort.
  
  
  CONCLUSIONS
  In the present analysis of rare SFTP, previously proposed staging systems were applicable for prediction of disease-free survival. Independently of treatment, MIB was the only sole predictive marker. A prospective multi-institutional database could be helpful in establishing detailed predictive criteria in patients diagnosed with SFTP.
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany. Electronic address: severin.schmid@uniklinik-freiburg.de.
authors.forename: Severin
authors.initials: S
authors.lastname: Schmid
authors.affiliation: Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Agnes
authors.initials: A
authors.lastname: Csanadi
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Jussuf Thomas
authors.initials: JT
authors.lastname: Kaifi
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Kübler
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Haager
authors.affiliation: Department of Pathology, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Gian
authors.initials: G
authors.lastname: Kayser
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Bernward
authors.initials: B
authors.lastname: Passlick
authors.affiliation: Department of Thoracic Surgery, University Hospital Freiburg, Freiburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wiesemann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D054363:Solitary Fibrous Tumor, Pleural / Q000737:chemistry / Q000401:mortality* / Q000473:pathology
chemical_list: D019394:Ki-67 Antigen
keywords: Fibrous tumors; Pleural fibroma; Prognosticators