Progressive facial hemiatrophy and epilepsy: a common underlying dysgenetic mechanism.

Progressive facial hemiatrophy (PFH), a rare disorder characterized by progressive and self-limited atrophy of the skin and the subcutaneous tissues, is often associated with epilepsy but the link between these two conditions is poorly understood. The cause of PFH remains unclear. We report four patients with PFH associated with partial epilepsy in whom brain MRI showed cerebral dysgenesis. The four patients (two men, two women; age range: 24 to 73 years) developed parasagittal PFH in their second decade. Seizures started before the age of 20 years in three patients and were refractory simple, or complex partial seizures. All the patients had focal MRI showing cortical dysgenesis, ipsilateral to PFH, consisting of cortex thickening, gyral effacement, and blurring of the white-gray interface. The underlying white matter was hyperintense on T2-weighted sequences, with nodular areas in two patients. These areas were stable over time, without contrast enhancement, and were consistent with the MRI characteristics of cystic encephalomalacia. These neuroradiologic features suggest a localized cerebral hemispheric defect of congenital origin. Because cells participating in the formation of the fronto-nasal bud derive from common progenitors with the cells that give rise to the cerebral hemisphere, we suggest that an early malformative process affecting one side of the rostral neural tube could underlie both cerebral dysgenesis and facial hemiatrophy.