title: Primary classical hemangiopericytomas of thorax.
abstract: BACKGROUND
  Hemangiopericytoma, an uncommon hypervascular tumor, occurs anywhere in the body with capillary vessels originating from the pericyte. These tumors most frequently occur in the musculature of the lower extremities and retroperitoneum, but are rarely seen in the thoracic cavity. The objective of this study is to present primary classical hemangiopericytomas of the thorax together with a literature review.
  
  
  METHODS
  The postoperative pathologic records of 17,165 operations that were performed between January 1990 and December 2010 in the clinic were retrospectively searched, and the files of 6 cases with the diagnosis of primary classical hemangiopericytoma were analyzed for clinical characteristics of patients, surgical procedures, histopathologic features, treatments after surgery, and morbidity and mortality results.
  
  
  RESULTS
  There were 4 female and 2 male patients with an average age of 30.3 years (range, 15 to 60 years). Three patients had thoracic wall lesions, 2 patients had intrathoracic extrapulmonary lesions, and 1 patient had mediastinal lesion. Four left and two right posterolateral thoracotomies were performed. Chest wall resection was performed in 3 patients, intrathoracic extrapulmonary mass excision in 2 patients, and mediastinal mass excision and left lower lobectomy in 1 patient. Postoperative histopathologic diagnoses were primary classical hemangiopericytomas in 4 patients and primary classical malignant hemangiopericytomas in 2 patients. Four patients underwent reoperation for recurrence. In the follow-up period, 2 patients are still alive at 30 months and 14 years postoperatively; 3 patients died at 7, 8, and 16 years postoperatively. One patient was lost to follow-up. All 3 mortalities were related to the recurrence or distant metastasis of the tumor.
  
  
  CONCLUSIONS
  Although hemangiopericytomas are benign or malignant tumors, they generally display malignant behaviors. The risk of recurrence and distant metastasis occurs even many years after resection, suggesting that the prognosis becomes worse after each recurrence.
authors.affiliation: Department of Thoracic Surgery, Ataturk Education and Research Hospital for Chest Diseases and Thoracic Surgery, Kecioren, Ankara, Turkey. piyaren@gmail.com
authors.forename: Pinar
authors.initials: P
authors.lastname: Bicakcioglu
authors.forename: Ertan
authors.initials: E
authors.lastname: Aydin
authors.forename: Ali
authors.initials: A
authors.lastname: Celik
authors.forename: Funda
authors.initials: F
authors.lastname: Demirag
authors.forename: Nurettin
authors.initials: N
authors.lastname: Karaoglanoglu
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006393:Hemangiopericytoma / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000601:surgery; D012189:Retrospective Studies; D013899:Thoracic Neoplasms / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed