title: Orbital hemangiopericytoma in an Asian population.
abstract: OBJECTIVE
  Hemangiopericytoma is a very rare orbital tumor. The purpose of this study was to report the clinical and histopathological features of six cases of orbital hemangiopericytoma in an Asian population.
  
  
  METHODS
  Clinical and histopathological features were reviewed in six patients who were histopathologically confirmed as having primary orbital hemangiopericytoma in National Taiwan University Hospital between May 2001 and December 2010.
  
  
  RESULTS
  Among the six cases who were diagnosed as having primary orbital hemangiopericytoma, all lesions were reported as vascular tumors and featured branching "staghorn appearance" vessels. All patients, including one male and five females, presented with progressive proptosis and some associated symptoms such as extraocular motility limitation with diplopia, displacement of the globe, afferent pupillary defect, congested vessels of conjunctiva, or decreased visual acuity. On computed tomography, the orbital tumors tended to manifest as circumscribed masses with homogeneous medium-to-high enhancement with contrast studies. All six patients received surgical treatments, and four of them had additional radiotherapy. Three patients had recurrence after surgeries, and one of them had multiple metastases to lung and liver. All patients were still alive after a follow-up period of 5-10 years.
  
  
  CONCLUSIONS
  Orbital hemangiopericytoma has malignant potential, which may lead to local recurrence and/or metastasis. Histopathological findings alone are insufficient to predict the behavior of this tumor. Therefore, both clinical and histopathological findings are important to evaluate the treatment outcomes. Total excision accompanied with radiotherapy is suggested and long-term follow-up is required.
authors.affiliation: Department of Ophthalmology, School of Medicine, National Taiwan University Hospital, Taipei, Taiwan; Department of Ophthalmology, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.
authors.forename: Chi-Hsin
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Department of Ophthalmology, School of Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yi-Hsuan
authors.initials: YH
authors.lastname: Wei
authors.affiliation: Department of Ophthalmology, School of Medicine, National Taiwan University Hospital, Taipei, Taiwan; Department of Pathology, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Yeh
authors.initials: Y
authors.lastname: Peng
authors.affiliation: Department of Ophthalmology, School of Medicine, National Taiwan University Hospital, Taipei, Taiwan. Electronic address: liaosl89@ntu.edu.tw.
authors.forename: Shu-Lang
authors.initials: SL
authors.lastname: Liao
mesh_terms: D000328:Adult; D005260:Female; D006393:Hemangiopericytoma / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009918:Orbital Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery; D012189:Retrospective Studies
keywords: Asian population; orbital hemangio-pericytoma