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| CASE REPORT |
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| Year : 2013 | Volume
: 1
| Issue : 2 | Page : 70-74 |
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Craniofacial microsomia: A rare case report
Swapnali Yogesh Chaudhari
Department of Maxillofacial Radiology, Nivaran Dental Diagnostic Centre, Ghatkopar, Mumbai, Maharashtra, India
| Date of Web Publication | 21-Oct-2013 |
Correspondence Address:
Swapnali Yogesh Chaudhari
Department of Maxillofacial Radiology, Nivaran Dental Diagnostic Centre, Ghatkopar, Mumbai - 400 077, Maharashtra
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/2321-3841.120122
Craniofacial microsomia is a unique clinical presentation of "1 st and 2 nd arch syndrome" with asymmetrical craniofacial development along with conductive hearing loss. It involves the underdevelopment of the structures of the first and second pharyngeal arches: Maxilla, mandible, external and middle ear, facial and trigeminal nerves, muscles of mastication and overlying soft tissue. In this article, we report a case of craniofacial microsomia diagnosed based on clinical and cone beam computed tomography (CBCT) findings. CBCT scan revealed incompletely formed inner ear structures in association with craniofacial microsomia, rarely reported in the literature. Keywords: Condylar aplasia, cone beam computed tomography, craniofacial microsomia
How to cite this article:
Chaudhari SY. Craniofacial microsomia: A rare case report. J Oral Maxillofac Radiol 2013;1:70-4 |
| Introduction | |  |
Hemifacial microsomia (HFM) is a condition characterized by unilateral microtia, macrostomia and failure of formation of the mandibular ramus and condyle. The term HFM was used by Gorlin and Pindborg and they suggested that oculo auriculo-vertebral dysplasia may be a variant of HFM wherein, vertebral anomalies and epibulbar dermoids are also present. [1] HFM is also known as first arch syndrome, first and second branchial arch syndrome, otomandibular dysostosis, oculo auriculo-vertebral dysplasia and lateral facial dysplasia. [2] The name, craniofacial microsomia, was proposed by Converse et al. when cranial deformities are also present. [3]
HFM results from the abnormal development of the first and second branchial arches and the first branchial membrane. These arches are the mounds of tissue that contribute to the development of facial structures such as maxilla, mandible, zygomatic bone and ear. Neural crest cells migrate to the developing arches and are responsible for the correct formation of these structures. Damage to or disruption of these cells result in the facial abnormalities of HFM and related syndromes. [4]
In HFM, there can be the complete absence or underdevelopment of external and middle ear structures; however, inner ear anomalies are rare. In this article, a case of craniofacial microsomia is presented with its characteristic radiological features that will help us understand and diagnose this rare entity.
| Case Report | | |
A 14-year-old female patient was referred to the Nivaran Dental Diagnostic Center, Ghatkopar, India for a cone beam computed tomography (CBCT) scan. Patient had a history of facial asymmetry since birth and wanted to undergo corrective orthognathic surgery. The patient was conscious, cooperative and well-oriented. On extraoral examination, the left side of patient's face was hypoplastic [Figure 1]. In left external ear, only ear lobe was formed fully and was placed at the lower level as compared with the right side. There was complete hearing loss from the left side. The orthopantomograph [Figure 2] showed complete absence of the condyle and coronoid process of mandible on the left side. The left ramus of mandible was underdeveloped and the left antigonial notch was prominent. The CBCT scan revealed: | Figure 1: 3D reconstruction of soft-tissue demonstrating facial asymmetry
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 | Figure 2: Orthopantomograph showing absence of left condyle and coronoid process and hypoplastic left ramus of mandible
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- Hypoplasia of the left side of face [Figure 3].
 | Figure 3: 3D reconstruction of bone showing hypoplastic left zygomatic bone, left mandibular ramus. Left orbit is at the lower level than right orbit
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- Absence of left condyle and coronoid process [Figure 4].
 | Figure 4: 3D reconstruction of bone showing normal right condyle, coronoid process and ramus of mandible (a) and aplasia of left condyle, coronoid process and hypoplastic ramus of mandible (b)
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- Absence of left glenoid fossa.
- Hypoplastic left ramus of mandible.
- Hypoplastic left zygomatic arch [Figure 5].
 | Figure 5: Cone beam computed tomography axial image showing normal (a) and hypoplastic (b) zygomatic arch
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- Absence of external auditory canal and middle ear structures on the left side [Figure 6].
 | Figure 6: Cone beam computed tomography coronal image showing normal ear anatomy on the right side and absence of external auditory canal and middle ear structures on the left side (EAC = external auditory canal, IAC = internal auditory canal)
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- Absence of the mastoid air cells on the left side [Figure 7].
 | Figure 7: Cone beam computed tomography coronal image showing absence of the mastoid air cells on the left side
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- Underdeveloped inner ear structures on the left side [Figure 8].
 | Figure 8: Cone beam computed tomography coronal image showing underdeveloped inner ear structures on the left side
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On the basis of clinical and CBCT scan findings, the diagnosis of cranio facial microsomia was made.
| Discussion | | |
In 1881, German physician Carl Ferdinand Von Arlt first time described the condition craniofacial microsomia. [5] Exact etiology of HFM is not known, but laboratory studies suggest that an early loss of neural crest cells may be the specific factor responsible for the clinical presentation of HFM. [6] HFM is the second most common congenital facial anomaly after cleft lip/palate, with reported incidence of about 1 in 5,600 live births. [7]
The etiology is unresolved and complicated. Teratogenic and genetic components have been examined by many investigators. Reports indicate that several teratogenic agents, such as retinoic acid, primidone and thalidomide have produced HFM in infants born to pregnant women exposed to those agents. Poswillo produced facial anomalies in laboratory animals by maternal intake of 10 mg/kg thalidomide or 60 mg/kg triazene. He believed that either total or incomplete development of stapedial artery caused by an expanding hematoma could trigger a localized necrosis in the derivatives of first and second branchial arches, which would cause HFM. Granstrom also induced microtia and other craniofacial defects in rats by injecting excessive dose of retinoic acid or etretinate to pregnant rats. Research is leading in the direction of a suggestion that the possible etiological factor could be disruption in the blood supply to the first and second branchial arches in the 6-8 weeks of pregnancy. [7]
The clinical features of HFM include flattening of the face on the affected side due to hypoplastic maxillary and malar bones and aplasia of the mandibular ramus and condyle. The eye may thus appear to be on the lower level than that of the affected side. Malformation of the external ear may vary from complete aplasia to a crumpled, distorted pinna. [1] The chin and the facial midline are off-centered and deviated to the affected side. Often, one corner of the mouth is situated higher than the other, giving rise to an oblique lip line. [8] There can be hypoplasia of muscles such as the masseter, temporalis, pterygoids and muscles of facial expression on the involved side.
Mild to severe ear deformities in HFM have been reported. External ear abnormalities may be as mild as a flattened helical rim or as severe as complete absence of the auricle; stenosis or atresia of the external auditory canal can also be seen. Since the ossicles are also derived from the first and second branchial arches, abnormal development of the middle ear ossicles may be present in HFM. Consequently, conductive hearing loss as a result of external and middle ear malformations is common. [9]
In oral manifestations, there is macrostomia, aplasia of the mandibular ramus and condyle. [1] Agenesis of the third molar and second premolar may be present on the affected side as well as there can be the presence of supernumerary teeth, enamel malformations, delay in tooth development and hypoplastic teeth. [8]
Based on the clinical features, there are two classification systems for HFM: the skeletal-auricular-soft tissue and the orbital asymmetry-mandibular hypoplasia-ear malformation-nerve dysfunction-soft tissue deficiency classification. [10],[11]
HFM can be easily confused with Treacher Collins syndrome More Details. The differentiating features are: HFM is unilateral, it is not hereditary and colobomas of the lower lids do not occur in HFM. [1]
Radiographically, extraoral radiographs and orthopantomograph reveal aplasia of the mandibular ramus and condyle, hypoplastic maxillary and zygomatic bone. On the basis of clinical and radiographic findings, final diagnosis of HFM can be made. Advanced imaging such as computed tomography (CT) and CBCT is required when correction of the facial asymmetry is planned with orthodontic treatment and orthognathic surgery. Also, when sensorineural hearing loss or facial nerve dysfunction is present, CT or magnetic resonance imaging (MRI) may be advised.
MRI is helpful to study the hypoplasia of facial muscles and to study the facial nerve in patients with HFM. MRI can also be used to study the temporomandibular joint mainly the articular disc and condyle relationship, when surgical procedures like mandibular distraction osteogenesis are planned.
CBCT with its dual advantage of low radiation dose and high image resolution is becoming an integral part of dentistry. CBCT has various dental applications such as implant planning, precise localization of impacted teeth, to study various pathologies such as odontogenic cysts and tumors, temporomandibular joint disorders. CBCT is also helpful for paranasal sinus and temporal bone evaluation and airway analysis in sleep apnea cases. Direct volume rendering with CBCT generates excellent 3D images which are very helpful for orthognathic surgeries. In advanced CBCT software, there is an option of superimposition, in which the follow-up scan can be superimposed on the old scan to study the treatment outcome. In the present case, the 3D images were generated with CBCT as per the requirements of referring oral surgeon. CBCT scan revealed aplasia of left mandibular condyle and coronoid process, absence of left glenoid fossa, hypoplasia of left mandibular ramus, hypoplastic left zygoma and zygomatic arch. When temporal bone was studied carefully, there was a complete absence of external and middle ear structures on the left side. Furthermore, there was the absence of the mastoid air cells and inner ear structures were underdeveloped.
A craniofacial team, which includes plastic Surgeons, Otolaryngologists, Orthodontists and Prosthodontists is involved in the treatment of HFM. The objective of this treatment is to restore the facial symmetry and proper functioning.
The purpose of this article is to add one new interesting case with typical clinical and radiological features of craniofacial microsomia and to point out that whenever such case is encountered, the dental radiologist should critically evaluate the temporal bone as inner ear anomalies though rare, can occur in association with craniofacial microsomia.
| References | | |
| 1. | Gorlin RJ, Pindborg JJ. Syndromes of the Head and Neck. New York: McGraw-Hill; 1976. p. 261-5. 
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| 2. | James DR, Baggs PR. Craniofacial anomalies. In: Adams DA, Chinnamond MJ, editors. Scott-Brown's Pediatric Otolaryngology. 6 th ed. Oxford: Butterworth-Heinemann; 1997. p. 1-53.
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| 3. | Converse JM, McCarthy JG, Woodsmith D, Coccaro PJ. Craniofacial microsomia. In: Converse JM, editor. Reconstructive Plastic Surgery. 2 nd ed. Philadelphia: W.B. Saunders; 1977. p. 2359-400.
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| 4. | Sze RW, Paladin AM, Lee S, Cunningham ML. Hemifacial microsomia in pediatric patients: Asymmetric abnormal development of the first and second branchial arches. AJR Am J Roentgenol 2002;178:1523-30.
|
| 5. | Gorlin RJ, Jue KL, Jacobsen U, Goldschmidt E. Oculoauriculovertebral dysplasia. J Pediatr 1963;63:991-9.
|
| 6. | Monahan R, Seder K, Patel P, Alder M, Grud S, O'Gara M. Hemifacial microsomia. Etiology, diagnosis and treatment. J Am Dent Assoc 2001;132:1402-8.
|
| 7. | Kapur R, Kapur R, Sheikh S, Jindal S, Kulkarni S. Hemifacial microsomia: A case report. J Indian Soc Pedod Prev Dent 2008;26 (Suppl 1):S34-40.
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| 8. | Moulin-Romsée C, Verdonck A, Schoenaers J, Carels C. Treatment of hemifacial microsomia in a growing child: The importance of co-operation between the orthodontist and the maxillofacial surgeon. J Orthod 2004;31:190-20.
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| 9. | Carvalho GJ, Song CS, Vargervik K, Lalwani AK. Auditory and facial nerve dysfunction in patients with hemifacial microsomia. Arch Otolaryngol Head Neck Surg 1999;125:209-12.
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| 10. | David DJ, Mahatumarat C, Cooter RD. Hemifacial microsomia: A multisystem classification. Plast Reconstr Surg 1987;80:525-35.
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| 11. | Vento AR, LaBrie RA, Mulliken JB. The O.M.E.N.S. classification of hemifacial microsomia. Cleft Palate Craniofac J 1991;28:68-76.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
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