A Pediatric Case of Synovial Sarcoma of the Mediastinum Totally Resected by Staged Surgery

Abstract

Synovial sarcoma is a malignant soft tissue tumor that commonly occurs in the vicinity of the large joints in young adults. We report the case of a 14-year-old girl with synovial sarcoma of the mediastinum, a rare location and age for the disease. She was referred to our hospital with the diagnosis of superior vena cava syndrome. Computed tomography revealed a tumor located in the upper superior mediastinum, extending into the superior vena cava and the right atrium. There were also multiple metastases in the liver and lung. Since ultrasound examination showed an enlarged tumor abutting the tricuspid valve, semi-urgent surgery was performed to resect the tumor in the right atrium. Histopathological analysis showed epithelial elements and SYT-SSX2 gene rearrangement, leading to the diagnosis of monophasic epithelial-type synovial sarcoma. Postoperative chemotherapy induced an impressive response with the tumor and metastases shrinking. A second surgery was performed to resect the remaining tumor, and complete resection was achieved. After this resection, metastases to the brain and lung were discovered. The patient underwent cranial radiation and the lung lesion was operatively resected. Unfortunately, the patient had a cerebral infarction resulting in death 2 years and 11 months after the initial surgery. This case report documents the successful gross resection of a rare pediatric synovial sarcoma of the mediastinum with multiple metastases and cardiac involvement. Despite initial success, this patient’s untimely death reveals the aggressiveness of this rare tumor and the challenges of treating aggressive and uncommon malignancies.