Treacher Collins Syndrome

Clinical History

A 28-year-old male presented with difficulty eating, nasal regurgitation during eating and conductive deafness bilaterally. All other developmental milestones were normal. Clinically, the head was dolichocephalic with antimongoloid slanting palpebral fissures and sparse eyelashes. The nose was prominent.

Imaging Findings

Computed Tomography of face and paranasal sinuses revealed deviation of the nasal septum towards the right side with a bony spur touching the medial wall of the right maxillary sinus. The pinna were normal with relatively hypoplastic external auditory canals bilaterally. Middle ear cavities were small bilaterally with hypoplastic ear ossicles. Bilateral mastoid cavities were hypoplastic and non-pneumatized.

The left zygomatic arch was completely absent. Only a small anterior portion of the right zygomatic arch was visualized with absence of the rest of the zygomatic process.

The maxilla was narrow and overprojected, though both maxillary antra were normal.

The hard palate was narrow and elevated with a bony defect posteriorly on the left side. The mandible was mildly hypoplastic with an obtuse mandibular angle.

Marked flattening of the articular eminence of temporo mandibular joint was seen bilaterally.
Hypoplasia of the right medial pterygoid was also noted.

Discussion

Treacher Collins syndrome (TCS), also called mandibulofacial dysostosis, is a rare genetic disorder due to bilateral malformation of first and second branchial arches [1]. It is characterized by distinctive abnormalities of the head and face. The syndrome is named after Edward Treacher Collins (1862–1932), the English surgeon and ophthalmologist who described its essential traits in 1900 [2,3]. Mutations in TCOF1, POLR1C, or POLR1D genes can cause this syndrome [4].

Craniofacial abnormalities tend to involve the zygomatic bones, jaws, palate and oral cavity (mouth) which can lead to breathing (respiratory) and feeding difficulties.
There is anomalous development with all or most of the following features: eyelids (antimongoloid slanting or shortened palpebral fissures, lower lid colobomas, absent eyelashes), mandible (hypoplasia, dental malocclusion, retracted chin), maxilla (narrow or overprojected maxilla, elevated or narrow palate), malar bone (small or absent zygomatic arches), nose (broad or protruded), ears (absent external auditory canal, middle ear malformation, pinna deformity) and/or mouth (microstomia) [1,5,6]. Findings are often bilateral and symmetric. There is reduced upper airway volume with severe narrowing of the retroglossal space so apnea as well as speech and hearing difficulties are common [7]. Conductive hearing loss results from dysembryogenesis of the middle and external ears.

Treatment during the first year of life involves correction of colobomas. Surgical correction of the zygoma, orbit, and mandible are usually not performed until the patient is 4–10 years of age.

Our patient had characteristic antimongoloid slant, prominent nose with maldevelopment of facial and skull bones involving nasal septum, hard palate, zygomatic bones, maxilla, mandible, external auditory canals, middle ear and mastoid leading to a diagnosis of TCS. However there were no colobomas.

Differential Diagnosis List

Final Diagnosis

Treacher Collins Syndrome

URL:	https://www.eurorad.org/case/14128
DOI:	10.1594/EURORAD/CASE.14128
ISSN:	1563-4086