Myogenic Sarcoma of the Left Parapharyngeal Space in a Case Report

Ni Tang
Department of Oncology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000
Xuejing Xiang
Department of Oncology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000
Yuanyuan Luo
Department of Oncology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000
GUI Yan
Department of Oncology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000

Abstract:

Myogenic Sarcomas (MS) are rare malignant soft tissue tumors, accounting for approximately 0.3%-0.5% of all soft tissue sarcomas, and are prevalent in the head and neck region. Clinical occurrence in the parapharyngeal space is extremely rare. Its pathology is complex, including rhabdomyosarcoma, smooth muscle sarcoma and other subtypes. Due to the lack of specific molecular markers, clinical diagnosis often needs to be combined with immunohistochemistry and molecular testing, which makes the treatment more difficult. A 51-year-old male with MS of the parapharyngeal space was admitted to our hospital with clinical manifestations of hoarseness, accompanied by headache and oropharyngeal discomfort. Imaging examination showed a 2.3X4.1 occupying lesion in the left parapharyngeal space, encircling the internal carotid artery, and pathologic biopsy confirmed sarcoma, which tended to be of myogenic origin. For this rare case, the treatment team adopted an innovative comprehensive plan: radical intensity-modulated radiotherapy (total dose of 70.4 Gy/32 times) combined with the targeted drug amilorotinib (10mg/d, two weeks oral and one week off) and epirubicin + isocyclophosphamide two-drug chemotherapy (epirubicin 50mg d1-2/40mg d3 + isocyclophosphamide 2g d1-5, 21 days as a cycle). Follow-up MRI 3 months after treatment showed a reduction in tumor volume, significant improvement in symptoms, and no radiological nerve damage. There was no local recurrence or distant metastasis at 6 months of follow-up. Literature search showed that there were no previous reports of parapharyngeal space MS treated with a triple combination regimen of simultaneous targeted-chemotherapy with radiotherapy. This case suggests that a comprehensive strategy of precision radiotherapy combined with multi-targeted and cytotoxic drugs based on anatomical characteristics may overcome tumor heterogeneity through synergistic effects and provide a new direction for the treatment of MS at special sites, but more cases need to be accumulated and long-term efficacy evaluated.