From the standpoint of diagnostic practice, CD34 stains is almost never positive in synovial sarcoma, but this stain in the current case is focal, weak and somewhat vague. HWCK and EMA are more sensitive markers to confirm the epithelial differentiation of SS, TLE-1 is a more specific marker for SS. The morphological appearance of this tumor is not indicated of the diagosis of the so-called malignant hemangiopericytoma/ cellular solitary fibrous tumor, one should not to make any definite diagnosis relying on IHC alone without consideration of the morphology context. CD99 is a less specific marker and can be expressed in many SBRCTs such as PNET, SS, rhabdomyosarcoma. lymphoma and small cell variant osteosarcoma.
From the standpoint of diagnostic practice, CD34 stains is almost never positive in synovial sarcoma, but this stain in the current case is focal, weak and somewhat vague. HWCK and EMA are more sensitive markers to confirm the epithelial differentiation of SS, TLE-1 is a more specific marker for SS. The morphological appearance of this tumor is not indicated of the diagosis of the so-called malignant hemangiopericytoma/ cellular solitary fibrous tumor, one should not to make any definite diagnosis relying on IHC alone without consideration of the morphology context. CD99 is a less specific marker and can be expressed in many SBRCTs such as PNET, SS, rhabdomyosarcoma. lymphoma and small cell variant osteosarcoma.