Download benign masticatory muscle Hypertrophy

Pictorial CME
Benign Masticatory Muscle Hypertrophy
Anugrah Chrispal, Hari Kishan Boorugu
Fig. 1 : Facial profile of patient showing hypertrophied temporalis and
masseter
Fig. 2 : MRI image of the head (coronal section)
showing homogenous enlargement of bilateral
masseter and temporalis muscles.
A 32 year old Indian male presented with progressive painless swelling of both jaws and temporal regions. The patient was otherwise
asymptomatic and denied history of bruxism. Clinical examination revealed bilateral non-tender swelling over both mandibles and
temporal fossae (Figure 1). Systemic examination and dental examination was normal. Magnetic resonance imaging (MRI) of the head
revealed a homogenous increase in the bulk of the masticatory muscles – bilateral temporalis and masseter (Figure 2). The option of
Botulinum toxin injection was offered to the patient.
Idiopathic masticatory muscle hypertrophy is a relatively rare disorder which usually manifests in late adolescence or early adulthood.1
Hypertrophy of the masseters was first described by Legg in 1880.2 There are a few theoretical explanations for the etiology of masticatory
muscle hypertrophy, but the precise etiology is not clear.1 The most common of these, bruxism is associated with psychosocial stress,
anxiety, malocclusion and sleep disorders.3 Masseter hypertrophy is known to occur in isolation or with temporalis muscle hypertrophy
but temporalis hypertrophy without hypertrophy of masseters is very rare.4 Clinical diagnosis of masseter hypertrophy could be
difficult in unilateral cases and differential diagnosis in such patients includes parotiditis, parotid tumor, lipoma, vascular tumors,
benign or malignant muscle or mandibular tumors.1 Computed tomogram, magnetic resonance imaging and ultrasonogram can be
used to confirm muscle hypertrophy.1 Milder cases do not require therapy, or merely reassurance or tranquilizers; however in severe
cases or for cosmetic considerations botulinum toxin type A or surgery can be considered.1,5
References
1.
Sannomya EZ, Goncalves M, Cavalcanti MP. Masseter muscle hypertrophy: case report. Braz Dent J. 2006;17:347-50.
2.
Tauber T, Starinsky R, Varsano D. Ultrasonographic and computed tomographic diagnosis of benign masseteric hypertrophy. Pediatr Radiol
1986;16:238-239.
3.
Balatsouras D, Kaberos A, Psaltakos V, Papaliakos E, Economou N. Bruxism: two case reports. Acta Otorhinolaryngol Ital 2004;24:165-70.
4.
Da Silva K, Mandel L. Bilateral temporalis muscle hypertrophy: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2006;102:e1-3.
5.
Kim JH, Shin JH, Kim ST, Kim CY. Effects of two different units of botulinum toxin type a evaluated by computed tomography and
electromyographic measurements of human masseter muscle. Plast Reconstr Surg 2007;119:711-7.
Department of Medicine Unit 2, Christian Medical College and Hospital, Vellore 632004, Tamil Nadu, India
Received: 14.04.2009; Accepted: 02.05.2009
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© JAPI • november 2009 • VOL. 57