Synovial sarcoma
| Classification according to ICD-10 | |
|---|---|
| C49 | Malignant growth of other connective tissue and other soft tissue |
| ICD-10 online (WHO version 2019) | |
The synovial sarcoma or synovialoma is a malignant tumor that originates from the connective tissue and belongs to the soft tissue sarcomas . Microscopically, the tissue resembles the synovial membrane , although it is believed that it is not derived from it, but rather arises from primitive mesenchymal cells .
Epidemiology
Overall, synovial sarcomas are very rare. However, after rhabdomyosarcoma , they represent the most common type of sarcoma among children and adolescents . Calculated across all age groups, they account for around 8% of all soft tissue sarcomas. The peak of illness is between 20 and 30 years. Men are affected slightly more often than women. In principle, synovial sarcomas can occur anywhere in the body, but the lower extremities are preferred and especially the area around the large joints.
histology
There are two distinguishable tissue types: on the one hand, a biphasic synovial sarcoma, which consists of epithelial cells arranged like a gland in a spindle cell group , and the monophysical type, which is composed only of spindle cells.
genetics
Synovial sarcomas are predominantly characterized by a translocation of the X chromosome and chromosome 18 . The fusion of two normal genes, on the one hand SYT and on the other hand one of two largely homologous genes, SSX1 or SSX2 , results in a fusion gene, which is then read and codes for a pathological fusion protein. How this leads to the development of the tumor is not yet fully understood. However, the type of fusion gene correlates with the histological subtype and the biological behavior of the sarcoma.
clinic
The slowly growing tumors are usually well demarcated and often contain cystic parts, which is why they are easily mistaken for benign changes. Pain is usually absent at the beginning, but can arise in the course of the compression of surrounding structures. Months, sometimes years, can pass between the first signs and the diagnosis. A histological examination is decisive for the diagnosis . The size of the tumor is an important risk factor for metastasis , which usually occurs in the lungs . The treatment is carried out by surgery, additional local radiation and, if necessary, chemotherapy. The prognosis is favorable for small, non-metastatic sarcomas with high cell differentiation. Large, metastatic synovial sarcomas that cannot be completely removed are associated with a poor prognosis.
Web links
Individual evidence
- ^ Duden.de: Synovialoma
- ↑ Kawai et al .: SYT-SSX Gene Fusion as a Determinant of Morphology and Prognosis in Synovial Sarcoma , N Engl J Med 1998; 338: 153-160, DOI: 10.1056 / NEJM199801153380303
