A case of vulvar superficial angiomyxoma with necrotizing angiitis-like lesions and expression of granulocyte-colony stimulating factor

A vulvar tumor of 3-year-old girl was resected. The tumor had a pedunculated polypoid appearance with a multinodular surface and was covered by normal colored skin. Histologically, the tumor was lobulated and consisted of sparse stellate- or spindle-shaped tumor cells with a large amount of edematous stroma admixed with myxomatous areas. The tumor was rich in blood vessels of various sizes. Several blood vessels showed fibrinoid necrosis. There was a diffuse neutrophilic infiltration in the stroma. The tumor was diagnosed as a superficial angiomyxoma. Immunohistochemically, the tumor cells diffusely expressed vimentin, focally α-smooth muscle actin and desmin. Both estrogen and progesterone receptors were negative. Occasionally, they expressed CD34. Most of the tumor cells expressed granulocyte-colony stimulating factor (G-CSF). Endothelial cells of tumor blood vessels occasionally expressed intercellular adhesion molecule-1 or E-selectin. Some endothelial cells in the tumor were immunolabeled by anti-vascular endothelial growth factor (VEGF) antibody along their luminal surfaces. In the present case, G-CSF and adhesion molecules to neutrophils may have played some roles in neutrophilic infiltration into the tumor and in fibrinoid necrosis of the blood vessels. In addition to these molecules, VEGF may have contributed to vascular growth, leading to edematous stroma.