Synovial Sarcoma : Immunostains CK
Most synovial sarcomas show immunoreactivity for cytokeratins and EMA. In biphasic synovial sarcoma, cytokeratin staining is stronger in the epithelial component than in the spindle cell component (as shown here). In monophasic fibrous type of synovial sarcoma (and in the spindle cell component of biphasic synovial sarcomas), the immunoreactivity for these markers is patchy and inconsistent. Most poorly-differentiated variants also express these markers. Cytokeratins 7 and 19 are usually positive in a greater proportion of tumor cells than EMA and AE1/AE3. Others have found consistent expression of CK7, CK14, CK8/18 and CK19 in the epithelial cells of biphasic tumors. Image courtesy of: Michael Cascio, MD (@mjcascio); used with permission.