부산대학교 도서관

Desmoid-type fibromatosis is a soft tissue tumor formed by fibroblast proliferation that tends to infiltrate surrounding tissue but does not give rise to metastases. The stomatognathic area of the mandible is considered to be a relatively common site. Most of the previous reports are of advanced cases, and onset occurs mainly in young patients. There are many reports on treatment methods, including surgery, pharmacotherapy, and radiotherapy, so it can be difficult to decide on a treatment method. For the purpose of formulating a medical treatment for desmoid-type fibromatosis, the first edition of the guidelines for the treatment of extra-abdominal desmoid-type fibromatosis was published in Japan 2019. We report a case of desmoid-type fibromatosis arising in the masseter muscle of a 64-year-old man. His chief complaint was trismus. At initial presentation, a palpable small tumor was discovered in the left cheek. T2-weighted MRI showed a hyperintense area of about 10 mm in the left masseter muscle. Cytology ruled out malignancy, so an excisional biopsy was performed. The tumor was found in the masseter muscle. The tumor was about 15 mm and was diagnosed as desmoid-type fibromatosis by histopathological examination. We found no previous report of a tumor localized to the masseter muscle in an extensive search of the literature from the past 12 years. This case was considered to be a case of early treatment for the onset of illness at an advanced age. Two years after surgery, no recurrence has been observed.