The malignant peripheral nerve sheath tumor (MPNST) originates from neurofibromatosis type 1 (NF1). Because NF1 patients have many accompaniments with growth of additional masses, they usually overlook potential malignant changes in their masses. Our patient had two growing mass near the left elbow for several months; however, she ignored these masses until 7 days prior to writing this article, at which time they began bleeding. Traditionally, sarcoma including MPNST treatment consisted of amputation of the involved extremity. However, treatment now consists of surgical resection with adjuvant therapy. Therefore, we conducted resection of the mass and subsequent coverage with a local advancement flap. We believe that the most effective treatment for MPNST is early diagnosis and fast surgery, coupled with notification that there is always potential for malignant change in NF1 patient’s masses.