|Year : 2016 | Volume
| Issue : 2 | Page : 110-114
Asmita Nandre, Prashant Patil
Department of Oral Medicine and Radiology, Navodaya Dental College, Raichur, Karnataka, India
|Date of Web Publication||9-Aug-2016|
Department of Oral Medicine and Radiology, Navodaya Dental College, Raichur, Karnataka
Source of Support: None, Conflict of Interest: None
An asymmetric variation of facial structures is commonly seen in the general population. Hemimandibular hyperplasia (HH) is a gross asymmetry of facial structures, characterized by unilateral enlargement of hard and soft tissues. The etiology of HH remains unknown; however, abnormalities involving the hormones, neural system, vascular, lymphatic, and mechanical influences have been proposed. The condition does not warrant any active intervention, except for cosmetic reasons. A case of a 22-year-old male showing characteristic features of HH is reported with insight on differential diagnosis. The case is presented to supplement existing clinical knowledge.
Keywords: Differential diagnosis, facial asymmetry, hemimandibular hyperplasia
|How to cite this article:|
Nandre A, Patil P. Hemimandibular hyperplasia. Saudi J Oral Sci 2016;3:110-4
| Introduction|| |
Facial asymmetry, characterized as correspondence in the size, shape, or relationship of two sides of the face, has high correlation with facial harmony, attractiveness, and beauty., It was first noticed by the early Greek artists and the term “normal facial asymmetry” was used. The word symmetry is derived from Greek symmetria which means “of like measure.” Later, Leonardo da Vinci and Albrecht Durer described the classic concept of human facial symmetry and found absolute bilateral symmetry a normal morphologic characteristic.
The etiologic factors that cause facial asymmetries and their underlying mechanisms are not yet completely understood., It is appropriate to classify facial asymmetries into the two basic categories of developmental and acquired asymmetries. Developmental asymmetries include agenesis, hypoplasia, hyperplasia, atrophy, hypertrophy, and malposition of the facial bony structures. Acquired asymmetries occur as a result of traumas, infections, functional shifts, and tumors. Affected patients usually report late in the course of the disease due to slow, progressive nature of the problem.
| Case Report|| |
A 22-year-old male reported to the Department of Oral Medicine and Radiology, Navodaya Dental College, Raichur, with a chief complaint of deviation of chin toward the left side for 2–3 years. The patient noticed the deviation of chin starting at the age of 18 years and was progressive in nature. There was no history of trauma, pain, paresthesia on the affected side.
Clinical examination revealed facial asymmetry, deviation of chin to the left side, increase in vertical height of the middle and lower thirds of face on the right side. Mouth opening was normal with deviation toward the left side [Figure 1] and [Figure 2]. Temporomandibular joint (TMJ) movements were bilaterally synchronous; no clicking on opening or closing was noticed, but tenderness was present on the right side of TMJ. Excursion and protrusive movements were not restricted. Dental occlusion was Class I malocclusion with anterior cross-bite. Midline shift was noticed toward the left side [Figure 3]. Full complements of teeth were present. No asymmetry of arch form was noted. Mandibular occlusal radiograph showed increase in width of bone on the right side [Figure 4].
|Figure 4: Occlusal radiograph showing enlargement of the right side of body of mandible|
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A panoramic radiograph revealed a discrepancy in size and morphology between the right and left condyles, enlargement of the right condyle, and elongation of the right ascending ramus as well as an enlargement of the skeletal base of the right hemimandible in all its dimensions. The gonial angle was characteristically rounded off, and the mandibular canal was displaced toward the lower border of the mandible [Figure 5].
|Figure 5: Orthopantogram enlargement of the right condyle and elongation of the right ascending ramus as well as increase in width of ramus of mandible|
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A posteroanterior skull radiograph revealed deviation of mandible toward the left side with facial asymmetry [Figure 6]. TMJ open and close view showed enlargement of the right condyle.
|Figure 6: Posteroanterior skull radiograph showing deviation of mandible toward the left side with facial asymmetry|
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Computed tomography scan revealed hyperplasia of body, condyle, angle, and ramus of the mandible on the right side and atrophy of the muscles of the masticator space on the right side with fatty proliferation noted in the soft tissue [Figure 7] and [Figure 8].
|Figure 7: (a and b) Computed tomography scan (axial and coronal sections) showing hyperplasia of body, condyle, angle, and ramus of mandible on the right side and atrophy of the muscles of the masti cator space on the right side|
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|Figure 8: (a and b) Three-dimensional reconstructed images revealed hyperplasia of body, condyle, angle, and ramus of mandible, zygomatic bone on the right side compared to the left side of mandible and increase in vertical height of the right side of body and ramus of mandible|
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On the basis of these clinical and radiological findings, the patient was diagnosed of having hemimandibular hyperplasia (HH).
| Discussion|| |
HH was clearly described by Obwegeser and Makek in 1986. HH is a rare malformation of nonneoplastic origin characterized by a three-dimensional enlargement of one side of the mandible, i.e., the enlargement of one side of the condyle, the condylar neck, and the ascending and horizontal rami. The anomaly terminates exactly at the symphysis of the affected side, and for this reason, it is called HH. Clinically, this malformation is characterized by facial asymmetry and shifting of the midline of the chin to the unaffected side. The unilateral asymmetric increase in facial height gives right to a sloping rima oris, but the mouth can be opened without restriction. In the present case, all these features were present including enlargement of the right side of zygomatic bone which was an additional observation.
The etiology of HH is still a matter of discussion in the literature. Genetic factors, circulatory problems, hormonal disturbances, traumatic lesions, and arthrosis have been proposed to be etiologic factors of the disease. The epidemiological data have suggested that there are similar incidences in both sexes and all ethnic groups.,
HH was clearly described by Obwegeser and Makek and must be distinguished from solitary and exclusive hyperplasia of the condyle. In condylar hyperplasia, radiographically, the condyle is homogenously enlarged, but the horizontal ramus is not increased in height and mandibular canal is not displaced; clinically, the facial appearance is distorted with an increase in the height of the affected side. An open-bite and cross-bite might be present on the affected side. Normally, the dental midline is deviated toward the unaffected side but may also be centered, depending on the vector and speed of growth. Hemimandibular elongation was first described by Obwegeser and Makek and is a developmental deformity of unknown etiology affecting the mandible unilaterally. It commonly presents with a progressively increasing transverse displacement of the chin point in young adulthood.
Obwegeser and Makek  stated that abnormal condylar growth regulates the abnormal growth of the mandibular body in both HH and unilateral condylar hyperplasia. However, in the patient described above, the situation differs significantly from patients with both classical HH and condylar hyperplasia. The patient presented with no elongation of either the condyle or the condylar neck; however, the condyle showed enlargement. The alveolar bone around the mandibular right first and second molars was enlarged, and enlargement of the right side body, condyle, angle, and ramus of the mandible with the involvement of zygomatic bone was noticed.
Rowe  described the criteria for true hemihypertrophy. According to him, hemifacial hypertrophy is an unusual condition which produces facial asymmetry by a marked unilateral localized overgrowth of all the tissues in the affected area, i.e., facial soft tissues, bone, and teeth. Hemihypertrophy can be localized enlargement of the mandible with accelerated dental development 10; however, in the present case, teeth were not affected.
In 2001, Khorsandian et al. reported a case of HH in a female patient with marked facial asymmetry due to increased right ramus and mandibular width and height without deviation of mandible and bilaterally symmetrical condyles. However, in the present case, condyles are asymmetrical with the involvement of zygomatic bone.
In 2007, Kaya et al. treated case of HH a 27-year-old female patient and observed transverse deviation of occlusal plane which canted down on the affected side (skeletal Class III occlusion), which was not observed in our case. The differential diagnosis for facial asymmetry can be varied including condylar hyperplasia, facial hemiatrophy, facial hemihypertrophy, and fibrous dysplasia [Table 1].
The correction of facial asymmetry in HH is purely cosmetic.
The treatment protocol for HH was advocated by Wolford  which includes as follows:
- Perform low condylectomy
- Reshape the condylar neck
- Perform orthognathic surgery
- Perform an inferior border ostectomy.
| Conclusion|| |
Facial asymmetry due to HH can pose diagnostic dilemma; however, with detailed history and clinical examination accompanied by thorough radiographic evaluation, the true nature of the condition can be unearthed. Since the condition is benign and slowly progressive, reassurance is all that may be required in most cases. Surgical correction is warranted if gross facial asymmetry is present causing cosmetic problem.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]