Fibrous Dysplasia of Bone

Fibrous dysplasia is a disease which may be manifested in a single bone as tumefaction or a solitary cyst (monostotic type), in a region involving contiguous bones, or in a diffuse manner (polyostotic type), the latter possibly in association with endocrine and developmental disturbances. The condition is of interest to the neurological surgeon when the cranial or cranio-facial structures are involved, and often the problem may be one of diagnosis rather than of therapy. Neurosurgical consideration becomes necessary when the cranial involvement simulates the changes often seen in association with a meningioma, or when the progress of the disease produces cranial tumefaction or encroaches upon intracranial structures. The following two cases illustrate these conditions. Case 1. The patient was a 14-year-old Negro girl admitted to the hospital in December 1950 because of diffuse enlargement of the left frontal region. Very little detailed history could be obtained other than that general enlargement and increasing prominence of the left frontal region and brow had been apparent over a period of at least six months, in association with some mild local discomfort. There was a history of diplopia, but apparently neither the visual disturbance nor the pain had been of sufficient severity to cause any marked discomfort. The clinical findings were related to the skull. There was bony prominence of the left frontal and frontotemporal region which also involved the outer two-thirds of the supraorbital ridge. The bony lesion extended upwards for a distance of about 4 to 5 cm., and laterally into the temporal region for a similar distance. In the frontotemporal region the prominence was moderately well defined, but the lesion itself was not sharply delineated at any point. There was a suggestive fulness of the left zygomatic region but no apparent involvement of the mastoid area. The left globe appeared to be displaced downward and possibly slightly forward, although extraocular muscle function was grossly normal. The overlying scalp was not unusual and could be moved freely. The neurological examination was otherwise within normal limits. X-rays disclosed a marked increase in density involving the lower and outer portion of the left frontal bone, the roof of the orbit, and the lateral wall of the orbit, with extension posteriorly to involve the sphenoidal ridge.