Table II.

Histological, immunohistochemical and cytogenetical characteristics of the more frequent subtypes of STS of the upper extremities.

Sarcoma type	Histology	IHC	Cytogenetics
UPS	Cytological and nuclear pleomorphism	Positivity for antigens suggesting diverse lines of differentiation in the same tumor.	Great number of genetic alterations. Phenotypic spectrum of a single molecular entity with myxoid fibrosarcoma.
SS	Biphasic: Spindle cell component with an epithelial component. Monophasic: Entirely compounded by the spindle component.	CK, EMA, S100, TLE1 positive.	Translocation t(X;18)(p11;q11) (90% of cases); fusion gene SSX-SYT.
ES	Epithelial and spindle cells that form nodules.	Vimentin, CK, EMA positive. SMARCB/INI1 negative.	No conclusions about the genetic aberrations can be drawn due to the low incidence of this tumor.
CCS	Spindle or polygonal cells with abundant cytoplasm disposed in nests with fibrous tracts between them.	Vimentin, HMB-45, S100, Melan-A positivity	Translocation t(12;22)(q13;q12); fusion gene EWS-ATF1.

All data were obtained from reference (6). STS, soft tissue sarcomas; UPS, undifferentiated pleomorphic sarcoma; SS, synovial sarcoma; ES, epithelioid sarcoma; CCS, clear-cell sarcoma; IHC, immunohistochemistry.