Immunohistochemical features of positive cytokeratin and negative vimentin can identify the anaplastic carcinoma component from the bizarre stromal components of the nodule.
Biopsy of the nodule and atrophic plaque revealed dense proliferation of spindle-shaped tumor cells from the dermis to the subcutaneous adipose tissue, and positive immunostaining for CD34 and vimentin in addition to negative staining for factor XIIIa and α-smooth muscle actin.
One of the two scalp lesions was accompanied by a nodule of cartilage and a meshwork of pseudovascular spaces, which were decorated with antibodies to vimentin and epithelial membrane antigen consistent with meningothelial tissue.