Angiosarcoma Arising in a Patient with a 10-Year-Old Hemangioma

Figure 4

A well-circumscribed area of high grade angiosarcoma. The tumor cells are large and polygonal with abundant cytoplasm, which corresponds to the epithelioid variant. The nuclei are very atypical and pleomorphic, with large nucleoli and irregular nuclear outlines; abnormal mitoses are present. The abundant pigment and prominent nucleoli led to the consideration of a melanoma; however, melanoma markers were negative, and the pigment is hemosiderin.