Imaging of facial anomalies

Anomalies of the face may occur in its lower or middle segments. Anomalies of the lower face generally involve the derivatives of the branchial apparatus and therefore manifest as defects in the mandible, pinnae, external auditory canals, and portions of the middle ears. These anomalies are occasionally isolated, but most of them occur in combination with systemic syndromes. These anomalies generally do not occur with respiratory compromise. Anomalies of the midface may extend from the upper lip to the forehead, reflecting the complex embryology of this region. Most of these deformities are isolated, but some patients with facial clefts, notably the midline cleft syndrome and holoprosencephaly, have anomalies in other sites. This is important because these patients will require detailed imaging of the face and brain. Anomalies of the midface tend to involve the nose and its air-conducting passages. We prefer to divide these anomalies into those with and without respiratory obstruction. The most common anomalies that result in airway compromise include posterior choanal stenoses and atresias, bilateral cysts (mucoceles) of the distal lacrimal ducts, and stenosis of the pyriform (anterior) nasal aperture. These may be optimally evaluated with computed tomography (CT) and generally require immediate treatment to ensure adequate ventilation. Rare nasal anomalies that also result in airway obstruction are agenesis of the pharynx, agenesis of the nose, and hypoplasia of the nasal alae. Agenesis of the nasopharynx and nose are complex anomalies that require both CT and magnetic resonance imaging (MRI). The diagnosis of hypoplasia of the nasal alae is a clinical one; these anomalies do not require imaging studies. Besides facial clefts, anomalies of the nose without respiratory obstruction tend to be centered around the nasofrontal region. This is the site of the most common sincipital encephaloceles. Patients with frontonasal and nasoethmoidal encephaloceles require both CT and MRI. In these patients, imaging of the brain is essential. Patients with suspected extranasal, intranasal, or mixed heterotopia may need images with CT or MRI or both. The last of the anomalies in this region is the presence of ectodermlined tracts and sinuses that may or may not be accompanied with masses. When these masses are located in the midline, they are almost always dermoids, whereas masses located off-midline may also be epidermoids. This latter group of anomalies is important because of its potential communication with the intracranial contents and the possibility of infection. Adequate imaging may require both CT and MRI. Midline facial clefts may be divided into common and complex. Common clefts represent the great majority and are isolated cosmetic defects that generally do not require imaging studies. Complex facial clefts with hypertelorism are almost always a part of the holoprosencephalies; imaging of the brain is more important than is imaging of the cleft proper. The studies should be obtained with MRI. Complex facial clefts in the presence of hypertelorism are most likely related to the midline cleft syndromes. This very rare and intricate group of disorders is generally accompanied with severe brain and eye anomalies. Imaging of these patients is better performed with both CT and MRI. We review common and uncommon facial anomalies. We have tried to approach them according to their clinical importance by dividing them into those with and without airway compromise.