Primary monophasic synovial sarcoma of the chest wall in an adolescent: a case report

BACKGROUND: Synovial sarcoma is a rare malignant mesenchymal tumor, accounting for 5-10% of soft tissue sarcomas, mainly affecting adolescents and young adults near large joints. Thoracic involvement, particularly in the chest wall, is extremely rare. Diagnosis is difficult due to histologic overlap with other tumors, requiring immunohistochemistry and molecular detection for confirmation. Treatment involves complete surgical excision with adjuvant therapy, guided by a multidisciplinary approach. CASE PRESENTATION: A 15-year-old Arab male presented with right upper limb numbness, pain, and progressive dyspnea. Physical examination revealed a firm, non-tender supraclavicular mass above the right clavicle, with mild edema of the right upper extremity. Chest radiography showed a right apical opacity with mediastinal shift to the left. Contrast-enhanced computed tomography (CT) demonstrated a large, heterogeneous mass originating from the right upper chest wall, extending into the lower cervical region, displacing the trachea, encasing the subclavian vein, and infiltrating adjacent neural and muscular structures. CT-guided biopsy confirmed a diagnosis of monophasic synovial sarcoma. The patient underwent complete surgical excision with vascular reconstruction, followed by referral for adjuvant oncologic therapy. CONCLUSIONS: Primary chest wall synovial sarcoma is a rare and diagnostically challenging tumor. Early recognition, accurate histopathological confirmation, and multidisciplinary management with complete surgical resection are essential to optimize outcomes and reduce the risk of recurrence or metastasis.