title: [Sinonasal-type hemangiopericytoma: a clinicopathologic analysis of 6 cases].
abstract: OBJECTIVE
  To study the clinicopathologic features, histologic diagnosis and differential diagnosis of sinonasal-type of hemangiopericytoma (SNTHPC).
  
  
  METHODS
  The clinical, radiographic and pathologic findings of 6 cases of SNTHPC were analyzed. Immunohistochemistry and electron microscopy were performed on selected examples.
  
  
  RESULTS
  Amongst the 6 patients studied, 4 were males and 2 were females. The age of patients ranged from 56 to 71 years (mean = 60.5 years old). The commonest clinical presentation was nasal obstruction and/or epistaxis. Other symptoms could include increased nasal secretion, eyeball pain, decreased visual acuity, increased tear secretion and headache. The tumor involved nasal cavity and/or paranasal sinuses. Gross examination showed polypoid tumor masses, brownish fleshy tissue or whitish tumor tissue fragments. Histologically, the tumor showed a mixture of diffuse, fascicular, storiform, reticulated and whorled growth patterns. The tumor cells were spindle-shaped and possessed clear to eosinophilic cytoplasm. Mitotic figures were rarely seen. The intervening vasculature was characteristically thin-walled, with focal hyalinization changes and rarely the staghorn pattern. Immunohistochemical study showed that the tumor cells expressed vimentin (6/6), smooth muscle actin (5/6) and CD34 (3/6). Electron microscopy demonstrated the presence of intracytoplasmic myofilaments. The tumor cells were linked together by primitive cell junctions. In general, the histologic diagnosis of SNTHPC was difficult, and only 1 case had the correct initial pathologic diagnosis made. Follow-up data were available in 5 patients and 2 of them had local recurrences.
  
  
  CONCLUSIONS
  SNTHPC is a low to intermediate grade soft tissue tumor with pericytes differentiation. Correct diagnosis relies on detailed pathologic assessment and application of ancillary investigations.
authors.affiliation: Department of Pathology, Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai 200031, China.
authors.forename: Shu-yi
authors.initials: SY
authors.lastname: Wang
authors.forename: Xiong-zeng
authors.initials: XZ
authors.lastname: Zhu
mesh_terms: D000199:Actins / Q000378:metabolism; D000368:Aged; D018952:Antigens, CD34 / Q000378:metabolism; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006393:Hemangiopericytoma / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D009296:Nasal Cavity / Q000473:pathology; D009364:Neoplasm Recurrence, Local; D010255:Paranasal Sinus Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D010256:Paranasal Sinuses / Q000473:pathology; D014746:Vimentin / Q000378:metabolism*
chemical_list: D000199:Actins; D018952:Antigens, CD34; D014746:Vimentin; C498862:Acta2 protein, rat