Abstract
Undifferentiated pleomorphic sarcoma (UPS) of the skin is a rare soft tissue sarcoma subtype with a high risk of metastasis and local recurrence. Ultraviolet exposure plays a prominent role in its etiology. Herein, we present two rare cases of UPS of the skin with an occurrence in non-ultraviolet exposed locations and discuss the need of wide resection and the identification of the depth of the tumor. Due to the resection of the skin, resulting defect was undertaken with skin grafting. One case was extending to the fascia and, after the resection, vacuum-assisted closure therapy was used for the formation of granulation tissue. No recurrence was seen after three and four years for either cases. In conclusion, UPS is a rare, aggressive malignant tumor with a high local recurrence and metastasis rate. Suspicion of malignancy in a plaque-like or nodular lesion in the skin is crucial, and local recurrence and metastasis risk is significantly correlated to the success of wide excision.