Unprecedented presentation of pelvic synovial sarcoma: A compelling case report

Synovial sarcoma (SS) is a rare tumor that typically arises in various body regions, with its manifestation in the abdominal-pelvic area being exceptionally uncommon. However, despite its rarity in this location, it often metastasizes to the thorax. Despite its slow growth, it can be misdiagnosed as benign in less than 10% of cases. Diagnosis necessitates identification of the SYT-SSX fusion transcript, alongside immunohistochemical and cytogenetic assessments. Treatment involves surgical resection followed by radiotherapy for localized tumors, while chemotherapy is necessary for metastatic cases. Despite treatment, synovial sarcomas have a high recurrence rate, with about half recurring within two years. We report the case of a 73-year-old patient from sub-Saharan Africa who presented to the emergency room with obstructive symptoms, revealing a mass near the anus compressing the rectum upon imaging, causing an obstructive syndrome. Despite initial tumor resection, histological analysis identified a neurofibromatous origin. Twenty months later, recurrence prompted a hospital visit, revealing thoracic metastases necessitating surgery and chemotherapy. Subsequent analysis confirmed perianal synovial sarcoma. This case underscores the rarity of pelvic-anal synovial sarcoma and emphasizes the importance of early detection and proper management. Synovial sarcoma should figure prominently on the list of differential diagnoses of high-grade pelvic masses due to the importance of adjuvant chemotherapy.