Pleomorphic hyalinizing angiectatic tumor of soft parts - Immunohistochemical study including the expression of vascular endothelial growth factor

We report morphologic, flow cytometric, and immunohistochemical findings in two cases of pleomorphic hyalinizing angiectatic tumor of soft parts. Both patients were middle-aged women with subcutaneous lesions located in the l ower extremity. The tumors consisted of sheets of spindled and pleomorphic cells with frequent intranuclear pseudoinclusions associated with clusters of ectatic vessels surrounded by prominent perivascular hyaline material. N umerous, nonhyalinized vessels were also present, mostly in the peripheral areas of the lesions. Some of these vessels had their walls permeated by nu merous small capillaries. Immunostaining for vascular endothelial growth fa ctor (VEGF), a secreted protein that has been implicated in tumor-associate d angiogenesis, demonstrated positive staining in both tumoral and endothel ial cells. Tumor cells were also reactive to vimentin and CD34. Focal posit ivity for CD99 and factor XIIIa was also present. Flow cytometry yielded a diploid DNA histogram with S-phase fraction of 7%. Our findings corroborate those from previously reported cases. They further suggest that angiogenes is and the angiogenic factor VEGF may play a role in the development of thi s peculiar tumor.