[Epileptic seizures as the first sign of fibrous bone dysplasia]

Fibrous bone dysplasia is an unusual disorder of the maturation of bone, seen as hyperostosis of the craniofacial bones and the diaphyses of long bones. Monostotic and polyostotic forms occur, depending on whether one or more bones are affected. The diagnosis is radiological (cranial CT or MR) or on morbid anatomy. The etiopathogenesis is not known. The association of epilepsy and monostotic fibrous bone dysplasia is rare. We present a case of monostotic fibrous bone dysplasia which presented with epileptic seizures.

A 28 year-old-woman had had undiagnosed epilepsy for 12 years. Neurological examination was normal and EEG findings non-specific. Cranial CT and MR suggested fibrous bone dysplasia. Since there was bilateral reduction of the visual fields, due to compression of both optic nerves, the affected bones were removed surgically. Anatomopathological study confirmed the diagnosis of fibrous bone dysplasia.

The association between epilepsy and monostotic fibrous bone dysplasia is unusual. Epilepsy may be an initial symptom in asymptomatic fibrous bone dysplasia. The mechanism for the production of epileptic seizures may not be related to compression phenomena or local ischemia, but be secondary to alteration in the mechanism of cAMP as the second messenger of the cerebral cortex. Patients with fibrous bone dysplasia should undergo neurological examination to rule out local compression with minimal clinical findings.