Brain Pathology Case of the Month - January 2011


DIAGNOSIS

CONGENITAL INTRAVENTRICULAR ATYPICAL MENINGIOMA, WHO GRADE 2 leading to a genetic diagnosis of NF2

DISCUSSION

Childhood meningiomas are a rare entity accounting for about 1.5% of all pediatric intracranial tumors as compared with adults where they constitute nearly one third of such masses (13). While in adults, meningiomas occur in the ventricular system in only 2% of the cases; the number of ventricular lesions in children is four to ten times higher (5-8). Thus, even though they are rare, pediatric meningiomas often pose a challenge to neurosurgeons. This report provides an interesting case of an unusually large atypical intraventricular meningioma in an infant.

Meningiomas in children are usually associated with NF2 or previous cranial irradiation. Perilongo et al.(10) reported that 23% of patients had evidence of neurofibromatosis II (11).

According to the criteria set by the WHO panel, diagnosis of atypical meningioma should be made when the tumor has an average mitotic rate of >4 per 10 hpf, or has 3 of the following 5 features: tumor necrosis; sheet-like patternless growth; small cells with high nucleocytoplasmic ratio; and hypercellularity. Two types of meningiomas, chordoid and clear cell, typically fit these criteria. In a recent review of 8 cases of childhood meningiomas, 2 were diagnosed as atypical with the youngest patient being 3 years old(1). In general, histopathology in childhood meningiomas shows a preponderance of grade I (>70%), with atypical being 2-4% and grade III as less than 5%. Atypical meningiomas however, have been reported to be as high as 20% in at least one case series (9).

Genetic testing for patients suspected of NF2 follows a sequence beginning with tumor cell DNA analysis in cases such as ours. If tumor cell DNA analysis shows NF2 mutations in both alleles, a study of the patient's constitutional DNA is indicated to look for a germline mutation. Of note is that germline nonsense NF2 mutations, such as seen in our patient, are associated with increased disease severity and an increase in the number of NF2-associated intracranial meningiomas (2). Constitutional nonsense and frameshift NF2 mutations are associated with severe, and missense mutations and somatic mosaicism are associated with mild disease (3,4,12) .

The current case illustrates an unusually large, congenital, intraventricular meningioma of atypical pathology in an infant. Given the age at presentation and the presence of constitutional NF2 mutations, this child is likely to eventually develop the multiple other lesions associated with the syndrome. The patient will, therefore, undergo early hearing testing, routine eye examinations and MRI screening for vestibular, other intracranial and spinal lesions starting at age 5 years (2).

REFERENCES

  1. Alexiou GA, Mpairamidis E, Psarros A, Sfakianos G, Prodromou N. Intracranial meningiomas in children: report of 8 cases. Pediatr Neurosurg 44: 373-5, 2008
  2. Evans DG. Updated 5/19/2009. Neurofibromatosis 2. In: Gene Reviews at Gene Tests: Medical Genetics Information Resource (database online). Copyright, University of Washington, Seattle. 1997-2009. Available at http://www.genetests.org. Accessed 9/30/2009
  3. Evans DGR, Trueman L, Wallace A, Collins S, Strachan T. Genotype/phenotype correlations in type 2 neurofibromatosis (NF2): evidence for more severe disease associated with truncating mutations. J Med Genet 35: 450-5, 1998
  4. Evans DGR, Wallace AJ, Wu CL, Trueman L, Ramsden RT, Strachan T. Somatic mosaicism: a common cause of classic disease in tumor-prone syndromes? Lessons from type 2 neurofibromatosis. Am J Hum Genet 63: 727-36, 1998
  5. Ferrante L, Acqui M, Artico M, Mastronardi L, Rocchi G, Fortuna A. Cerebral meningiomas in children. Childs Nerv Syst 5: 83-6, 1989
  6. Germano IM, Edwards MS, Davis RL, Schiffer D. Intracranial meningiomas of the first two decades of life. J Neurosurg 80: 447-53, 1994
  7. Liu M, Wei Y, Liu Y, Zhu S, Li X. Intraventricular meninigiomas: a report of 25 cases. Neurosurg Rev 29: 36-40, 2005
  8. Mallucci CL, Parkes SE, Barber P, Powell J, Stevens MC, Walsh AR, Hockley AD. Paediatric meningeal tumours. Childs Nerv Syst 12: 582-8, 1996
  9. Menon G, Nair S, Sudhir J, Rao BR, Mathew A, Bahuleyan B. Childhood and adolescent meningiomas: a report of 38 cases and review of literature. Acta Neurochir (Wien) 151: 239-44, 2009
  10. Perilongo G, Sutton LN, Goldwein JW, Gusnard D, Schut L, Biegel JA et al. Childhood meningiomas: Experience in the modern imaging era. Pediatr Neurosurg 18: 16-23, 1992.
  11. Perry A, Giannini C, Raghavan R, Scheithauer BW, Banerjee R, Margraf L et al. Aggressive phenotypic and genotypic features in pediatric and NF2-associated meningiomas: a clinicopathologic study of 53 cases. J Neuropathol Exp Neurol 60: 994-100, 2001
  12. Ruttledge MH, Andermann AA, Phelan CM, Claudio JO, Han F-Y, Chretien N et al. Type of mutation in the neurofibromatosis type 2 gene (NF2) frequently determines severity of disease. Am J Hum Genet 59: 331-42, 1996
  13. Tufan K, Dogulu F, Kurt G, Emmez H, Ceviker N, Baykaner MK. Intracranial meningiomas of childhood and adolescence. Pediatr Neurosurg 41:1-7, 2005 Zwerdling T, Dothage J. Meningiomas in children and adolescents. J Pediatr Hematol Oncol 24:199-20, 2002

Contributed by Muhammad Omar Chohan MD, Tausif Rehman MD, Rafael Medina-Flores MD, Carol Clericuzio MD, Richard Heideman MD, and Erich Marchand MD


International Society of Neuropathology