title: [Clinicopathological study of Ewing's sarcoma/primitive neuroectodermal tumor in oral and maxillofacial region].
abstract: OBJECTIVE
  To study the clinicopathological features and diagnostic criteria of Ewing's sarcoma/primitive neuroectodermal tumor (Ewing's sarcoma/PNET) in oral and maxillofacial region.
  
  
  METHODS
  There were 15 patients with Ewing's sarcoma/PNET in the last 35 years at our hospital, aged 1-49 years and mean 14.5 years. The most common manifestation was swelling of the affected region. The cases were analyzed and histological and immunohistochemical studies were also conducted to examine CD99 (12E7), Vimentin, NSE, S-100, Syn, CD45 (LCA), desmin.
  
  
  RESULTS
  (1) The most common histological pattern of Ewing's sarcoma/PNET was a lobular arrangement of uniform, small, hyperchromatic cells in a fibrous background. Some of these tumors were rich in cytoplasmic glycogen. (2) Of the 7 cases, IHC was positive for CD99 (12E7) and Vimentin and negative for lymphoid (CD45), muscle (desmin) markers. S-100 was positive in 4 cases and NSE negative in 3, Syn positive in 1. NSE, S-100, Syn were all negative in 2 cases.
  
  
  CONCLUSIONS
  Ewing's sarcoma/PNET is more common in teenagers and young people. Immunohistochemistry is essential to distinguish Ewing's sarcoma/PNET from other small round cell tumors. Immunohistochemistry is useful in the diagnosis.
authors.affiliation: Department of Pathology, West China School of Stomatology, Sichuan University, Chengdu 610041, China.
authors.forename: Hua-wei
authors.initials: HW
authors.lastname: He
authors.forename: Lai-kui
authors.initials: LK
authors.lastname: Liu
authors.forename: Yi-ning
authors.initials: YN
authors.lastname: Li
authors.forename: Dan
authors.initials: D
authors.lastname: Wang
authors.forename: Zhi-xiu
authors.initials: ZX
authors.lastname: He
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005153:Facial Neoplasms / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D007573:Jaw Neoplasms / Q000175:diagnosis / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018241:Neuroectodermal Tumors, Primitive, Peripheral / Q000175:diagnosis / Q000473:pathology*; D012512:Sarcoma, Ewing / Q000175:diagnosis / Q000473:pathology*; D055815:Young Adult