Figure 3.

Tumor cells were short and spindle-shaped, arranged in no overt architecture. The nuclei were oval, without prominent atypia. The intervening matrix was edematous and myxoid ((a); ×400;HE). In some regions, fine collagen as well as dense collagen was detected ((b); ×100;HE). The vast majority of blood vessels were small and thin-walled ((c); ×100;HE). Some medium-sized blood vessels were also identified within the lesion ((d); ×100;HE). There was no specific distribution pattern of the vascularity.