[Limited mouth opening - what now?]

This case report illustrates a rare complex of symptoms leading to limited mouth opening in a young woman. The 28-year old suffered from a progressively limited mouth opening over several years that finally resulted in restricted alimentation and made dental treatment impossible. Clinical findings suggest a structural alteration, including a hyperplastic mandibular angle and marked hypertrophy of the masseter muscle. Further radiologic investigations reveal a thickened aponeurosis of the masticatory muscles and hyperplastic coronoid processes that are not interfering with the zygomatic bone. Primary therapeutic options for such conditions are mainly surgical, including reduction of the masseter muscles volume and aponeurorectomy as well as bony reductions, such as coronoidectomy and mandibular angle reduction. With this treatment, the outcome and prognosis are good. Long-term results depend on concomitant physical therapy. A uniform nomenclature for this condition is yet lacking and propositions such as “masticatory muscle tendon-aponeurosis hyperplasia” have been made. However, knowledge of this condition and its typical clinical signs can make the diagnosis and treatment straightforward, thus leading to an improved quality of life of affected patients.