Published online Aug 16, 2021. doi: 10.12998/wjcc.v9.i23.6872
Peer-review started: April 15, 2021
First decision: May 10, 2021
Revised: May 20, 2021
Accepted: May 26, 2021
Article in press: May 26, 2021
Published online: August 16, 2021
Trismus is a common problem with various causes. Any abnormal conditions of relevant anatomic structures that disturb the free movement of the jaw might provoke trismus. Trismus has a detrimental effect on the quality of life. The outcome of this abnormality is critically dependent on timely diagnosis and treatment, and it is difficult to identify the true origin in some cases. We present a rare case of trismus due to fungal myositis in the pterygoid muscle, excluding any other possible pathogenesis.
The patient presented with a 2-mo history of restricted mouth opening. Computed tomography showed obvious enlargement of the left pterygoid muscles. Furthermore, the patient had trismus without obvious predisposing causes. The primary diagnosis was pterygoid myosarcoma. Consequently, lesionectomy of the left pterygoid muscle was performed. Intraoperative frozen biopsy implied the possibility of an uncommon infection. Postoperative pathologic examination confirmed myositis and necrosis in the pterygoid muscle. Fungi were detected in both muscle tissue and surrounding necrotic tissue. The patient recovered well with antifungal therapy and mouth opening exercises. The rarity of fungal myositis may be responsible for the misdiagnosis. Although the origin of pathogenic fungi is still unknown, we believe that both hematogenous spread and local invasion could be the most likely sources. To the best of our knowledge, this is the first case in the literature that reported fungal myositis in pterygoid muscles as the only reason that results in trismus.
Surgeons should remain vigilant to the possibility of trismus originating from fungal myositis.
Core Tip: Trismus has a detrimental effect on the quality of life. Early diagnosis and treatment have the potential to minimize the consequences of this condition. However, it is not always easy to identify the true origin in some cases. We report the first case in the literature that fungal myositis in pterygoid muscles is the only reason for trismus. We initially misdiagnosed this case of fungal origin because of its rarity. Surgeons should consider the possibility of fungal myositis in trismus diagnosis.