title: Clinical features of clear cell meningioma: a retrospective study of 36 cases among 10,529 patients in a single institution.
abstract: BACKGROUND
  Clear cell meningioma (CCM) is a rare subtype of meningioma. We present the largest series of 36 CCMs and evaluate several prognostic factors of patient's clinical outcome.
  
  
  METHODS
  Thirty-six patients with pathologically confirmed CCM among a total of 10,529 meningioma patients were retrospectively reviewed.
  
  
  RESULTS
  CCM constituted 0.3 % of the intracranial meningiomas and 1.4 % of the intraspinal meningiomas. The male-to-female ratio (36 vs 64 %) for CCMs was similar to that for total meningiomas (28 vs 72 %) patients (chi-squared test, p = 0.3). The mean age at diagnosis of CCM patients (29.3 ± 18.4 years) was significantly younger than that of total meningiomas (49.8 ± 11.9 years) patients (t-test, p = 0). During the follow-up, 15 patients (42 %) suffered from tumor recurrence. The recurrence time ranged from 10 months to 12 years, with a median time of 29 months. Kaplan-Meier survival analysis showed that patients after total resection (Simpson grades I and II) had significantly longer progression-free survival (PFS) time than those after subtotal resection (Simpson grades III and IV) (log-rank test, p = 0.006). However, age (≤20 years or >20 years, p = 0.9), gender (p = 0.3), postoperative radiotherapy (p = 0.4), progesterone receptor staining (positivity or negativity, p = 0.2), and Ki-67 index (≤5 % or >5 %, p = 0.4) did not have significant effects on patients' PFS time.
  
  
  CONCLUSIONS
  The proportion of CCM in spinal meningiomas is likely to be much larger than that in intracranial meningiomas. CCMs should be resected totally when possible to decrease the risk of recurrence or prolong patient's PFS time.
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Zhenmin
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Qiangyi
authors.initials: Q
authors.lastname: Zhou
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Xingchao
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Neural Reconstruction, Beijing Neurosurgery Institute, Capital Medical University, Beijing, China.
authors.forename: Fu
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Department of Neurosurgery, Beijing Tian Tan Hospital, Capital Medical University, 6, Tiantan Xili, Dongcheng District, 100050, Beijing, China. pinanliu@ccmu.edu.cn.
authors.forename: Pinan
authors.initials: P
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008579:Meningioma / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D011379:Prognosis; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen; D011980:Receptors, Progesterone
keywords: Clear cell meningioma; Clinical features; Prognosis; Retrospective study