Biphasic Synovial Sarcoma with Mesothelial Differentiation: Characteristics and Treatment
Synovial sarcoma is a rare type of soft tissue sarcoma that typically occurs in young adults. It usually arises in the extremities, particularly around the knees, but can also arise in other locations. Although synovial sarcoma is not mesothelioma, some rare cases of synovial sarcoma may exhibit mesothelial differentiation. These cases are referred to as biphasic synovial sarcoma with mesothelial differentiation.
Characteristics of Biphasic Synovial Sarcoma with Mesothelial Differentiation
Biphasic synovial sarcoma with mesothelial differentiation is a rare subtype of synovial sarcoma that exhibits both epithelial and mesenchymal differentiation. In these tumors, the mesothelial differentiation is characterized by the presence of both epithelial and mesenchymal components, such as glandular structures and spindle cells. The biphasic nature of these tumors means that they are composed of two distinct cellular components that are morphologically different from one another.
Biphasic synovial sarcoma with mesothelial differentiation typically presents as a soft tissue mass, often in the extremities. On imaging studies, these tumors may appear as heterogeneous masses with both solid and cystic components. Histologically, these tumors are composed of both glandular and spindle cells, and may exhibit stromal hyalinization and calcification.
Biphasic synovial sarcoma with mesothelial differentiation typically expresses epithelial markers such as cytokeratins, as well as markers of mesenchymal differentiation, such as vimentin and CD99. The diagnosis of these tumors requires histologic examination and immunohistochemical analysis, which can differentiate them from other soft tissue tumors with similar histologic features.
Treatment of Biphasic Synovial Sarcoma with Mesothelial Differentiation
The treatment of biphasic synovial sarcoma with mesothelial differentiation is similar to that of other soft tissue sarcomas. The mainstay of treatment is surgical resection, which aims to achieve negative margins. In some cases, radiation therapy or chemotherapy may be used in addition to surgery.
The prognosis of biphasic synovial sarcoma with mesothelial differentiation is generally favorable, with a 5-year survival rate of around 60-70%. However, the prognosis may depend on factors such as the location and size of the tumor, the presence of metastases, and the histologic grade of the tumor.
Conclusion
Biphasic synovial sarcoma with mesothelial differentiation is a rare subtype of synovial sarcoma that exhibits both epithelial and mesenchymal differentiation. These tumors typically present as soft tissue masses, and diagnosis requires histologic examination and immunohistochemical analysis. Treatment involves surgical resection, and the prognosis is generally favorable. Despite the rarity of these tumors, it is important for clinicians to be aware of their existence and to consider them in the differential diagnosis of soft tissue tumors.