Treacher-Collins syndromeThis case presents multiple radiological features of hemifacial microsomia, a condition characterised by hypoplasia of structures derived from the first and second branchial arches.

It is genetic  disease  characterisedassociated with extracranial anomalies in 55% of cases, as seen in this patient who has pentalogy of Fallot.

The main differential diagnosis is Treacher Collins syndrome, which is characterised by deformities ofbilateral involvement.

Another differential is Parry-Romberg syndrome, which is characterised by CNS and orbital manifestation and usually spares the ears, eyes, cheekbones, and chin and sometimes affect other systems as Heartear structures.

 It is estimated to occur in one in 10,000 to one in 50,000 births.

Differential diagnosis include Miller syndrome and Nager syndrome but in both syndromes additional limb anomalies are seen.

Facial asymmetry with underdeveloped right hemifacial bony and soft tissue structures as follows:

Osseous:

• small-sized, hypoplastic right mandibular condyle with foreshortened and underdeveloped right mandibular ramus and mild subsequent ipsilateral deviation of the chin to the right side

• small, hypoplastic right zygomatic arch

• small-sized right maxilla, maxillary antrum, and right pterygoid plate

Soft Tissue:

• small-sized right masseter, temporalis, and pterygoid muscles, as well as the overlying subcutaneous soft tissue

• absence of the right parotid gland

Auditory:

• right microtia with aplastic external auditory canal and middle ear cleft, as well as mastoid air cells

Additional Finding:

• right cerebellopontine angle arachnoid cyst