title: Recurrent orbital schwannomas: clinical course and histopathologic correlation.
abstract: BACKGROUND
  Schwannomas are slow-growing typically encapsulated tumors composed of differentiated Schwann cells, the primary class of peripheral glial cells. Complete excision is the treatment of choice for orbital schwannomas that cause pain, disfigurement, diplopia, or optic neuropathy. The presence of multiple schwannomas in a single patient suggests possible association with neurofibromatosis type 2 (NF2) or schwannomatosis.
  
  
  METHODS
  We present 2 patients who experienced recurrent orbital schwannoma without evidence for neurofibromatosis. The recurrence in one patient, a 59-year old man, occurred 6 years after complete excision of the initial tumor. This recurrence consisted of 2 independent tumors in the same orbit. The recurrence in the second patient, a 5 year-old girl, occurred multiple times within days to weeks of partial excisions until eventually a complete excision was performed.
  
  
  CONCLUSIONS
  The clinical history, histopathologic features and particularly the intraoperative findings suggest that the 59 year old man suffers from orbital schwannomatosis, while the rapid recurrence in the second patient correlated with the cellular features of her plexiform schwannoma. Hence, the recurrence in each patient is linked to a different etiology, with implications for treatment and patient counseling given the difficulty in treating orbital schwannomatosis. To our knowledge, this is the first description of isolated orbital schwannomatosis.
authors.affiliation: University of Michigan Medical School, Ann Arbor, MI, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Kron
authors.forename: Brenda L
authors.initials: BL
authors.lastname: Bohnsack
authors.forename: Steven M
authors.initials: SM
authors.lastname: Archer
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: McHugh
authors.forename: Alon
authors.initials: A
authors.lastname: Kahana
mesh_terms: D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D009442:Neurilemmoma / Q000473:pathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures / Q000379:methods*; D009918:Orbital Neoplasms / Q000473:pathology / Q000601:surgery*