Specific Tumors and Respective Markers

Atypical
fibroxanthoma (AFX)

Vimentin, actin, + histiocyte stains (i.e., CD68)

S100, pankeratin, CD34, CEA, EMA, desmin

Desmin, smooth muscle actin, ± vimentin

CEA, S100 (only rarely positive), keratin (only rarely positive)

S100, vimentin, melanA, HMB45 (latter negative in desmoplastic / spindle cell melanoma)

Keratin CD45 (also known as leukocyte common antigen or LCA), CEA, EMA, desmin

CD31, CD34, Factor VIII–related antigen, Ulex europaeus

Keratin, CEA, EMA, S100

Merkel cell
carcinoma (MCC)

CK 20, EMA, NSE, synaptophysin, chromogranin

S100, CD45, CEA, vimentin, desmin, GFAP, thyroid transcription factor-1 or TTF-1

Schwannoma
(Neurilemmoma)

Vimentin, S100, MBP

Keratin, neurofilaments, desmin

Vimentin, smooth muscle actin

Desmin (occasionally focally positive), cytokeratin

Cytokeratin, CD34 (50% cases), EMA, vimentin, ± CEA

Vimentin, CD34

S100, HMB45, keratin,
stromelysin-3, Factor XIIIa
(latter two markers positive in dermatofibroma)

CK7, EMA, CEA, GCDFP-15

S100, HMB45

EMA, keratin (CAM 5.2)

CEA (usually), S100

S100, NSE, MBP

GFAP, neurofilament