OBJECT: The hyperostosis frequently associated with sphenoid wing meningiomas is actual invasion of bone by the tumor. The intracranial portion of the tumor is usually thin with en plaque spread, and the tumor tends to invade the orbit through the superior orbital fissure. METHODS: The authors reviewed the records of 67 patients with sphenoid wing meningiomas who underwent surgery at the University of Arkansas for Medical Sciences between 1994 and 2004. In all 67 cases, the surgery was performed by the senior author. Seventeen of the patients had the distinguishing characteristics of hyperostotic sphenoid wing meningiomas-extensive bone invasion, en plaque dural involvement, and a minimal intracranial mass with minimal orbital involvement. In all patients, hyperostosis was determined on the basis of preoperative neuroimaging. Histopathological evaluation of bone specimens was performed in 14 cases. Estrogen and progesterone receptor expression and Ki 67 labeling were evaluated in all specimens. Chromosome analysis was performed in all tumors resected since 2001 (seven cases). Particular attention was paid to removing all involved bone and dura mater. RESULTS: Total removal was achieved in 14 cases (82.3%), with only one recurrence (7.1%) over a mean follow-up period of 36 months (range 5-72 months). Radical resection was followed by cranioorbital reconstruction to prevent enophthalmos and to obtain good cosmetic results. No deaths or serious complications occurred in association with surgery. Proptosis was corrected in all cases and visual acuity improved in seven (70%) of 10 cases. Revision of the orbital reconstruction was required because of postoperative enophthalmos (two cases) or restricted postoperative ocular movement (one case). CONCLUSIONS: Sphenoid wing meningiomas frequently invade bone, although such invasion does not represent malignancy. These lesions are generally histologically benign. Total removal with a prospect for cure and visual preservation should be the goal of treatment. This requires extensive drilling of the invaded bone and extensive excision of the involved dura. When the optic canal is involved, it should be decompressed. Extensive bone resection should be followed by cranioorbital reconstruction for good cosmesis and to prevent enophthalmos.