Arch Craniofac Surg > Volume 21(1); 2020 > Article |
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Tumors/markers | Cytokeratins (wide-spectrum) | p40 | Vimentin | S100 protein | HMB-45 | SMA | Desmin | CD68 |
---|---|---|---|---|---|---|---|---|
SpSCC | + | +/– | + | – | – | – | – | – |
Spindle cell melanoma | –/+ | – | + | + | –/+ | – | –/+ | +/– |
Atypical fibroxanthoma | – | – | + | – | – | –/+ | – | +/– |
Leiomyosarcoma | –/+ | – | + | –/+ | – | + | +/– | –/+ |
Angiosarcoma | –/+ | – | + | –/+ | – | – | – | –/+ |
This case (spindle cell component)b) | Positive | Positive | Positive | Negative | Negative | Negative | Negative | Negative |
+, positive in more than 90% of cases; –, negative; +/–, positive in 50% to 75% of cases; and –/+, usually negative, but anomalous expression may be seen in up to 25% of cases.
a) Cytokeratins are epithelial markers and subclassified according to molecular weight (MW). Low-MW cytokeratins appear in simple one-layered epithelium in gland and duct. High-MW cytokeratins appear in complex epithelium, such as the uroepithelium and skin. Along with the epithelial to mesenchymal transition, spindle cell squamous cell carcinoma may lose or downregulate cytokeratins and acquire vimentin expression. Thus, a panel of antibodies including multiple cytokeratin antibodies based on microscopic findings is recommended; p40 is a highly specific epithelial marker, vimentin is a nonspecific mesenchymal cell marker, and S100 protein and HMB-45 are melanocytic markers. S100 is more sensitive and less specific. Smooth muscle actin (SMA) and desmin are markers of myogenic origin, and CD68 is a nonspecific marker of fibrohistiocytic differentiation;