3 | DISCUSSION
Synovial sarcoma is generally considered a high-grade aggressive
sarcoma, with a poorer prognosis in adults than in
children[4]. Prognostic factors also include tumor
size, use of radiotherapy and/or chemotherapy, histological subtype, and
surgical margin status, among which tumor size >5 cm at the
time of treatment is consistently associated with poor
prognosis[5]. In addition, synovial sarcoma has a
high metastatic potential, and its metastatic rate can reach more than
50%[6]. The most common metastatic site is the
lung[7]. Other metastases include lymph, bone, and
liver, but patients with gastrointestinal metastases are rare. At
present, there were only a few dozen cases of metastatic synovial
sarcoma in the gastrointestinal tract had been reported in the
literature[8].
In addition to intestinal metastases, the patient was characterized by a
particularly rapid progression. It was only 20 days from the time of
admission to the patient’s death. Although this was related to the delay
in the patient’s visit to the hospital, the progression of metastases in
the patient after admission was very rare. The interval between two CT
scans was only 4 days, but the liver and intestinal metastases
progressed significantly. Due to the rapid progression, patients lost
opportunities for surgery and chemotherapy.
Synovial sarcoma has typical pathological and genomic features including
immunohistochemical features and a t(X;18)(p11.2;q11.2) chromosomal
translocation in which the SS18(SYT) gene (18q11) is associated with SSX
(including SSX1) , SSX2, SSX4, Xp11) gene fusion, resulting in the
generation of the SS18-SSX fusion gene, which occurs in most
patients[9]. Some RNAs may act in concert with
fusion genes to cause rapid tumor progression, but the exact map has not
yet been determined[10]. Gene sequencing of this
patient showed a significantly higher number of homozygous mutations
compared to conventional synovial sarcoma patients. The pathological
mechanisms involved in these mutated genes are all involved in immune
system exhaustion and tumor transcriptional dysregulation, which may be
the reason for the rapid tumor progression in this patient. Humoral and
cellular immunity, including the functional expression of T17 and Th
cells, may have certain relevance to the progression and prognosis of
synovial sarcoma[11]. Of course, this remains to
be verified by further research.