Calvarial defects associated with neurofibromatosis Type 1

Abstract

Calvarial osteolysis is a relatively rare finding in patients with neurofibromatosis. The authors describe two patients with neurofibromatosis Type 1 (NF1) and extensive cranial defects associated with underlying dural ectasia. Cranioplasties were performed in both patients with mixed results. One patient underwent cranioplasty using titanium mesh and methylmethacrylate. The other patient underwent an extensive cranioplasty with autogenous iliac crest grafting, and after initial healing has since had further bone resorption. In conclusion, the results of cranial reconstruction in patients with NF1 and dural ectasia are unpredictable because of the tendency for further bone resorption; techniques that protect the graft material from cerebrospinal fluid pulsations via a rigid mesh should be considered.

Congenital giant plexiform neurofibroma with occipital calvarial dysplasia in association with meningoencephalocele in neurofibromatosis Type 1 and segmental neurofibromatosis

“…8 cranial osteolysis in NF1 is very rare. 1,[6][7][8][9][10][11]13,17 There are only a few cases reported, and in most it is difficult to ascertain whether the osteolysis was a result of the erosion secondary to the giant tumor or was merely associated as part of the disease syndrome.…”

“…1,[6][7][8][9][10][11]13,17 There are only a few cases reported, and in most it is difficult to ascertain whether the osteolysis was a result of the erosion secondary to the giant tumor or was merely associated as part of the disease syndrome. 8 It is generally accepted that if there are no sclerosing margins of the bone defect and there is hypoplasia of the ipsilateral mastoid air cells, then the dysplasia is a true dysplasia and probably not due to the overlying defect.…”

“…The first and simplest explanation for osteolysis appears to be the associated mass lesion causing erosion of the overlying calvaria. 1,2,[6][7][8][9][10][11]13,14,16,17 The problem with this hypothesis was that none of the reports demonstrated radiological evidence of progression. calvarial osteolysis without mass lesions in NF has been described.…”

“…calvarial osteolysis without mass lesions in NF has been described. 8,14 Inherent dural ectasia and ballooning of the dura mater and subsequent erosion of the overlying calvaria has also been proposed. The exact mechanism, however, is a matter of conjecture.…”

“…The exact mechanism, however, is a matter of conjecture. 8 Defective mesodermal and neuroectodermal development has been proposed as an embryological mechanism.…”