Discussion
Gastrointestinal sarcoma accounts for 0.1% to 3% of all gastrointestinal (GI) malignancies and approximately 10% of all sarcomas. In the ileum, the majority of malignant sarcomas are GI stromal tumors (GISTs). To the best of our knowledge there have been only 27 reported cases of synovial sarcoma arising in the GI tract, and none of them in the ileum. All of them shared the diagnostic histology and immunohistochemical features of synovial sarcoma. In 64% of the cases, the characteristic (X; 18) translocation was identified. We made the diagnosis in our patient's case based on the histology of monophasic synovial sarcoma and the Immunohistochemical features. Although the molecular assay results were negative for SYT-SSX1 and SYT-SSX2, the combined histological and Immunohistochemical profiles were highly characteristic of monophasic synovial sarcoma.
The median age at diagnosis was 41.5 years (range, 14 to 75 years). There is no significant sex predilection with a male to female ratio of 1:1.15. There are 11 and 12 cases of GI tract synovial sarcoma arising from the esophagus (including one from the gastroesophageal junction) and stomach, respectively, representing the most common sites. The presenting symptoms were pain, obstruction or bleeding. The histological subtypes were monophasic in 15 patients and biphasic in 11 patients including two patients with a poorly differentiated component. The remaining patients' histological subtypes have not been reported. All of the reported cases were treated surgically. The number of patients who received adjuvant chemotherapy or radiotherapy or both are five, four and three, respectively. Only one patient had metastasis at first presentation. Billings reported a patient with gastric synovial sarcoma with multiple liver metastases who died of the disease after six months. The survival period after diagnosis of all reported cases ranged from 1 to 224 months (Table 1).
In soft tissue synovial sarcoma, numerous studies over the years have reported that it is a high grade malignancy with a high rate of metastasis leading to death; 10-year survival rates between 24% to 68% and 11% to 56% have been reported.
In the article by Bergh et al., the investigators divided patients with synovial sarcoma into low-risk and high-risk groups depending on their age, tumor size and grade as follows: low-risk group (patient age < 25 years, tumor size < 5 cm, and no histologic evidence of poorly differentiated tumor); high-risk group (patient age approximately 25 years, tumor size approximately 5 cm, and poorly differentiated tumor). The question is, can we apply the same risk factors to patients with GI synovial sarcoma? To answer such a question we need to diagnose more cases and collect more data about the already published cases to study the behavior of this disease entity in the GI tract, as well as in other parts of the body. Presently, the evidence suggests adequate primary surgery is essential to both local control and outcome. The other question that one may ask: why do these tumors shift to unusual sites and different tissues? The honest answer, at least at this time, would by that we do not yet know the exact mechanism for such a shift. We are involved in a larger research study to investigate the increased incidence of sarcomas in the Saudi population, particularly in the northern region, which is close to the military activities of both Gulf wars and the military activities in Iraq over the last decade.