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 Table of Contents  
CASE REPORT
Year : 2018  |  Volume : 5  |  Issue : 1  |  Page : 48-51

Bilateral coronoid hyperplasia causing limited mouth opening: A report of two cases


1 Department of Oral Medicine and Radiology, Government Dental College and Hospital, Aurangabad, India
2 Department of Oral Medicine and Radiology, Government Dental College and Hospital, Mumbai, India
3 Department of Dentistry, SBH Government Medical College and Hospital, Dhule, Maharashtra, India

Date of Web Publication8-Feb-2018

Correspondence Address:
Dr. Pooja Jain
Department of Oral Medicine and Radiology, Government Dental College and Hospital, Aurangabad, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jclpca.jclpca_101_17

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  Abstract 


Bilateral hyperplasia of the coronoid process of the mandible is an unusual entity which often presents with limited mouth opening. Thorough clinical and radiographic examination can help in the diagnosis and the treatment planning of this condition. This article consists of a case report of two patients. The patient in each case, presented with a reduced mouth opening, and when subjected to further investigations, was diagnosed with bilateral coronoid hyperplasia.

Keywords: Coronoid hyperplasia, diagnosis, trismus


How to cite this article:
Jain P, Gabhale SB, Kadam S, Agrawal P. Bilateral coronoid hyperplasia causing limited mouth opening: A report of two cases. J Cleft Lip Palate Craniofac Anomal 2018;5:48-51

How to cite this URL:
Jain P, Gabhale SB, Kadam S, Agrawal P. Bilateral coronoid hyperplasia causing limited mouth opening: A report of two cases. J Cleft Lip Palate Craniofac Anomal [serial online] 2018 [cited 2019 Aug 26];5:48-51. Available from: http://www.jclpca.org/text.asp?2018/5/1/48/224897




  Introduction Top


Coronoid hyperplasia is a condition, which is characterized by an elongation of coronoid process of the mandible. This is a developmental anomaly which is more commonly seen in males.[1] If the elongated coronoid process shows histologically normal bone tissue, it is called as hyperplastic.[2] At birth, the coronoid process is longer and larger than condyle, but as age advances, the condyle gradually achieves a higher position than the respective coronoid process.[3],[4]

Elongation of the coronoid process of the mandible was first described in 1853 by Von Langenbeckin.[2]

This condition generally progresses to asymptomatic trismus, which worsens with age and time. This article presents two cases of bilateral coronoid hyperplasia, of which the patients were unaware.


  Case Reports Top


Case 1

A 17-year-old male patient was referred to the department of oral medicine and radiology from the department of endodontics for the management of reduced mouth opening, which apparently caused difficulty during root canal treatment because of poor accessibility.

The patient had no history of trauma, and his medical and family histories were not significant. On examination, a maximum interincisal opening of 17 mm was noted. There was interdental spacing between the maxillary as well as mandibular incisors. Furthermore, the patient had an edge-to-edge bite of anterior teeth and an open bite of posterior teeth [Figure 1].
Figure 1: Reduced mouth opening (20 mm)

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There was no tenderness noted over the temporomandibular joint (TMJ) region. Mandible was hypomobile, and mandibular movements such as protrusion and lateral excursion were found to be restricted.

The patient was then subjected to radiographic examination. Panoramic and Water's view showed elongated coronoid process bilaterally. Cone-beam computed tomography (CBCT) of TMJ region was done for thorough examination of coronoid process in relation to the zygomatic bone. CBCT demonstrated an elongated coronoid process, going beyond the zygomatic bone [Figure 2], [Figure 3], [Figure 4]a and [Figure 4]b.
Figure 2: PA Water's view revealed bilaterally enlarged coronoid process

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Figure 3: Cone-beam computed tomography section revealed bilaterally enlarged coronoid process

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Figure 4: (a and b) Three-dimensional reconstruction (cone-beam computed tomography) revealed enlarged coronoid process on the right and left side, respectively

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The patient was then referred for scintigraphy to rule out an osseous activity at coronoid process. Scintigraphy showed an ongoing osseous activity, so the patient was kept under observation, and surgical intervention was delayed temporarily to prevent recurrence. The patient would be subjected to bilateral coronoidectomy after the growth of coronoid process ceases.

Case 2

An 18-year-old male patient was referred to the department of oral medicine and radiology from the department of oral and maxillofacial surgery for the management of reduced mouth opening, which apparently caused difficulty during extraction because of poor accessibility.

The patient had no history of trauma, and his medical and family histories were not significant. Intraoral examination revealed proclined maxillary incisors, crowding of maxillary and mandibular incisors, incompetent lips, and a maximum interincisal distance of 25 mm [Figure 5].
Figure 5: Reduced mouth opening (25 mm)

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The patient was not having tenderness over the TMJ region. Mouth opening and lateral excursion movements were restricted.

The patient was then subjected to radiographic examination. Panoramic view and Water's view showed noticeable enlargement of coronoid process bilaterally. For detailed examination, CBCT of TMJ region was done. CBCT demonstrated thickened triangular-shaped elongated coronoid process contacting the inferior aspect of zygomatic bone [Figure 6] and [Figure 7].
Figure 6: PA Water's view revealed bilaterally enlarged coronoid process

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Figure 7: Cone-beam computed tomography section revealed bilaterally enlarged coronoid process

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On the basis of clinical and radiological examination, diagnosis of bilateral coronoid hyperplasia was given. Scintigraphy was advised to rule out metabolic activity of bone growth at coronoid process, and reports showed negative results. This indicated that the patient could be surgically treated successfully as there was an absence of active bone formation at the coronoid process, ruling out any chances of recurrence following the surgical intervention.


  Discussion Top


Elongation of the coronoid process beyond normal, which is formed of histologically normal bone without any synovial tissue around it, is suggestive of hyperplasia.[5] Bilateral hyperplasia of the coronoid processes of the mandible is rare with a male and female ratio of 5:1, and it commonly occurs at the age of 14–16 years. Enlarged coronoid process impinges on the medial and anterior surfaces of the zygomatic arch, which leads to mandibular hypomobility. Occasionally, a pseudojoint develops between the hyperplastic coronoid process and the posterior surface of the zygoma, resulting in a condition, known as Jacob's disease.[6]

Kubota et al. conducted a study in which they compared the ratio between the length of the coronoid process and the length of the condylar process of patients with coronoid process hyperplasia to that of the control group. The comparison was done using Levandoski panoramic radiograph analysis, and they concluded that a ratio >1.1 indicates that an additional assessment is required to rule out the coronoid hyperplasia.[7]

Multiple theories have been postulated, regarding the etiology of coronoid hyperplasia which includes genetic factors, abnormal endocrinal stimuli, trauma, and hyperactivity of the temporal muscle, causing reactive elongation of the coronoid process, but the exact etiology is unknown.[5] According to Shira and Lister, the etiology is developmental due to the defect in cartilaginous growth centers in the coronoid process.[8]

Coronoid hyperplasia presents as a progressive painless reduction in the mouth opening which is caused due to an impingement of the enlarged coronoid process on the zygomatic bone. Coronoid hyperplasia can be diagnosed through radiography, i.e., orthopantomograph and Posteroanterior Water's view for initial diagnosis. This should be followed by an advanced radiography such as CBCT for precise details of the condition as two-dimensional imaging may not provide accurate details because of anatomical complexities of the facial region. CBCT is very helpful in assessment of the condition and visualizing the relation between enlarged coronoid process and zygomatic bone.[3]

Scintigraphy plays an important role in assessment of active growth at coronoid process. Hot spot formation which occurs due to an increase in bone turnover can be appreciated in all the three phases of scintigraphy while hot spot of bone inflammation can be appreciated only in the second phase (mesenchymal) of scintigraphy.[9]

Differential diagnosis of coronoid hyperplasia should include TMJ ankylosis and oral submucous fibrosis (conditions which result in trismus). The etiological factors and the findings of these conditions are very different from that of coronoid hyperplasia. Coronoid hyperplasia is nothing but a heightened physiopathologic reaction of the coronoid process because of an altered functioning of the adjacent structures rather than a direct consequence of the disease process.[10]

This condition can be treated by the removal of an enlarged portion of coronoid process. Intraoral coronoidectomy is the treatment of choice as it provides easy access to the coronoid process, decreases morbidity to the facial nerve, and also prevents unsightly scarring. However, there are chances of hematoma formation and fibrosis. Extraoral coronal flap approach, which reduces the chances of hematoma formation and prevents intraoral scarring, has been used occasionally.[4]

Posttreatment physiotherapies such as stretching exercises and shortwave diathermy are mandatory for proper rehabilitation after surgery.[11] Application of ice packs and steroid injections to reduce the postoperative swelling can be used as an adjunct to physiotherapy. Administration of diphosphonates, which suppresses the alkaline phosphatase levels, reduces bone turnover and osteoblastic activity can also be used as an adjunct. Muscle relaxants should be used to enhance the effect of physical therapy, which otherwise becomes difficult to be performed due to stiffness of the jaw muscles.[7]

In our first case, we decided to keep our patient under observation as scintigraphy showed bone growth in progress. The surgery would be planned after the bone growth completes, to rule out any recurrence in future.

In our second case, as the scintigraphy showed completion of the bone growth, the patient was advised to undergo a surgery, i.e., bilateral coronoidectomy, but the patient refused for surgery as he was content with his interincisal opening of 25 mm.

s

Coronoid process hyperplasia, as one of the causes of mandibular hypomobility, usually goes underdiagnosed, but a thorough clinical and radiographic examination will help in correct diagnosis and proper management, to rationalize the ultimate clinical outcome.

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

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Shultz RE, Theisen FC. Bilateral coronoid hyperplasia. Report of a case. Oral Surg Oral Med Oral Pathol 1989;68:23-6.  Back to cited text no. 1
[PUBMED]    
2.
Nayak S, Pradhan S, Bara DP, Patra S. Bilateral elongated coronoid process: A case report. IOSR J Dent Med Sci 2015;14:61-3.  Back to cited text no. 2
    
3.
Fernández Ferro M, Fernández Sanromán J, Sandoval Gutierrez J, Costas López A, López de Sánchez A, Etayo Pérez A, et al. Treatment of bilateral hyperplasia of the coronoid process of the mandible. Presentation of a case and review of the literature. Med Oral Patol Oral Cir Bucal 2008;13:E595-8.  Back to cited text no. 3
    
4.
McLoughlin PM, Hopper C, Bowley NB. Hyperplasia of the mandibular coronoid process: An analysis of 31 cases and a review of the literature. J Oral Maxillofac Surg 1995;53:250-5.  Back to cited text no. 4
[PUBMED]    
5.
Chauhan P, Dixit SG. Bilateral elongated coronoid processes of mandible. Int J Anat Var 2011;4:25-7.  Back to cited text no. 5
    
6.
Blanchard P, Henry JF, Souchere B, Breton P, Freidel M. Permanent constriction of the jaw due to idiopathic bilateral hyperplasia of the coronoid process. Rev Stomatol Chir Maxillofac 1992;93:46-50.  Back to cited text no. 6
    
7.
Kim SM, Lee JH, Kim HJ, Huh JK. Mouth opening limitation caused by coronoid hyperplasia: A report of four cases. J Korean Assoc Oral Maxillofac Surg 2014;40:301-7.  Back to cited text no. 7
    
8.
Shira RB. Limited mandibular movement due to enlargement of the coronoid process. J Oral Surg 1958;16:183-91.  Back to cited text no. 8
    
9.
Sudoł-Szopińska I, Cwikła JB. Current imaging techniques in rheumatology: MRI, scintigraphy and PET. Pol J Radiol 2013;78:48-56.  Back to cited text no. 9
    
10.
Chakranarayan A, Jeyaraj P. Coronoid hyperplasia in chronic progressive trismus. Med Hypotheses 2011;77:863-8.  Back to cited text no. 10
    
11.
Totsuka Y, Fukuda H. Bilateral coronoid hyperplasia. Report of two cases and review of the literature. J Craniomaxillofac Surg 1991;19:172-7.  Back to cited text no. 11
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]



 

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