Cranio-orbital-temporal neurofibromatosis is an uncommon subtype of neurofibromatosis 1 characterized by pulsatile exophthalmos, orbital neurofibromas, sphenoid wing dysplasia, expansion of the temporal fossa, and herniation of the temporal lobe into the orbit. The cause of the sphenoid wing dysplasia is uncertain. Reconstruction of the sphenoid defect, separating the orbit and cranial vault, has been problematic because of resorption of bone grafts. This reports illustrates one potential cause of the sphenoid defect and a possible cause of the bone graft resorption.