SMN1 and fibrosarcoma: The differential diagnosis includes leiomyoma (consists of intersecting bundles of smooth muscle cells; SMA positive, CD34 negative) [15], inflammatory pseudotumor (consists of myofibroblasts, fibroblast cells mixed with inflammatory cells, predominantly plasma cells, lymphocytes, as well as eosinophils; SMA positive, vimentin positive, and CD34 negative) [16], fibrosarcoma (forms a "herringbone" pattern; CD34 negative), and stromal tumor (CD117 and CD34 positive) [11].