Masticatory muscle hypertrophy

Last revised by Dalia Ibrahim on 17 Dec 2023

Masticatory muscle hypertrophy, also known as - and commonly presenting as - temporalis and masseter muscles hypertrophy, is a rare condition that affects the muscles of mastication and results in "pseudomasses". Commonly seen in anxious individuals with "bruxism" and in chronic gum chewing 1

It sometimes gives a "threatening" appearance to the face that can create morphopsychological conflict in a gentle individual resulting in the "minotaur syndrome" 9. It can also involve the lateral and medial pterygoid muscles.

The age of the patients ranges from 15 to 65 years with involvement of both sexes 3.

Commonly presents with bilateral cheeks and temporal swelling. It most commonly occurs bilaterally. Unilateral occurrence and isolated temporalis/masseter enlargement has also been reported but is rare 1.

It appears in imaging as muscle hypertrophy with uniformly increased muscle bulk and preserved signal intensity. The value of imaging in diagnosis is to exclude other causes of facial swelling like tumors, especially if unilateral.

Conservative management is usually considered in mild cases. Surgical options are warranted in cases complaining of facial disfigurement and those who develop psychological problems (e.g. minotaur syndrome) due to their facial appearance 9.

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Cases and figures

  • Case 1: bilateral
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  • Case 2: unilateral
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  • Case 3: bilateral
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  • Case 4: bilateral
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  • Case 5
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  • Case 6: unilateral
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  • Case 7
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