Best practices in diagnostic immunohistochemistry: pleomorphic cutaneous spindle cell tumors.

CONTEXT: Pleomorphic cutaneous spindle cell tumors can be difficult to distinguish solely on histologic grounds. The use of ancillary immunohistochemical studies can greatly assist in this differential diagnosis.

OBJECTIVE

To review histologic and immunohistochemical aspects of cutaneous spindle cell tumors and discuss a basic panel of markers to assist in the differential diagnosis.

DATA SOURCES: English-language literature published between 1981 and 2005.

CONCLUSIONS

A basic immunohistochemistry panel for high-molecular-weight cytokeratin, melanocytic markers (S100 protein, HMB-45, Melan-A), smooth muscle actin, desmin, and endothelial markers (CD31, CD34) is effective in diagnosing most cutaneous spindle cell tumors.