Idiopathic Masseter Muscle Hypertrophy

On friday one surgeon came to me and asked "Can I touch your face?", "Of course" I said and lifted my head a little bit. He asked to open and close my mouth, to tense and relax masseter muscles. After examination he diagnosed me masseter muscle hypertrophy. I have never heard of this condition and I never noticed that something is wrong with my jaw because I have a square-shaped face, so it is quite wide from the day I was born. My masseter muscles are bigger than normal but it is also not so big to notice a pathology. Anyway, when I came back home I started to read more about hyperthrophy of this muscle and here is what I found: 

Masseter muscle hypertrophy is uncommon condition that can occur unilaterally or bilaterally.  Pain may be a symptom, but most frequently a clinician is consulted for cosmetic reasons because the majority complain of facial asymmetry (I don't feel any pain, for example, but i do have asymmetric face).

The Masseter muscle is essential for adequate mastication and is located laterally to the mandibular ramus, and thus plays an important role in facial esthetics.

Majority cases report that hyperthropy of masseter muscle is caused by clenching, bruxing, or heavy gum chewing and this occurs primarily in younger patients. Some authors associate it with defective teeth, temporo-mandibular joint disorder, congenital and functional hypertrophies, and emotional disorders (stress and nervousness).

Diagnosis can be produced from clinical examination (I was diagnosed by examination), directed interview, panoramic x-ray, and muscle palpation.

Therapy for masseteric enlargement is usually unnecessary, because it have no effect if it left untreated but for cosmetic reasons Masseter muscle can be cured both surgically or non-surgically. 

Surgical treatment usually involves resection of a portion of the Masseter muscle with or without the underlying bone.

(Intraoperative view)

(Hypertrophic muscle removed)

(Resected masseter mucle)

(Resected angle)

Non-surgical modality of treatment include reassurance tranquilizer or muscle relaxant, psychiatric care and injection of very small dose of botulin toxin type A (That's what treatment surgeon suggestested for me). When botulinum toxin type A is injected into a muscle it causes interference with the neurotransmitter mechanism producing selective loss of muscle function and a decrease in the mass of the muscle.

Sources:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3275871/

http://www.cochrane.org/CD007510/MOVEMENT_botulinum-toxin-type-a-for-masseter-hypertrophy

http://www.scielo.br/img/revistas/rboto/v74n5/en_a24fig01.jpg

https://static.kenhub.com/images/library/997/content_content_Masseter_muscle.png

http://www.hindawi.com/journals/crid/2012/521427/

http://cdn2.anunico-st.com/foto/2013/01/azzalure_botulinum_toxin_xeomin_botox_botulinum_toxin_type_a_for_sale-50f84a94c5db43185d6acc86a.jpg