Sarcoma epithelioid monophasic synovial

Weidner N, Goldman R, Johnston J. Epithelioid monophasic synovial sarcoma. Ultrastruct Pathol. 1993 17 287-294. 

Given the many clinicopathologic similarities between EPS (especially its proximal variant) and the very rare purely epithelioid synovial sarcoma, it would follow that they are difficult to separate by immunophenotypic analysis. A helpful discriminant between these neoplasms is CD34, which is present in EPS but not in epithelioid synovial sarcoma. Moreover, as cited above, Kato and associates found that nearly all EPS cases were immunoreactive for CA125, whereas synovial sarcomas lacked that marker. As mentioned earlier in this discussion, monophasic spindle-cell synovial sarcoma is consistently reactive for nuclear TLEl protein however, that moiety has not been studied specifically in the monophasic epithelioid variant. 

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