Immunostaining for TLE-1 cytokeratin 7/19 and demonstrating the t(X; 18) translocation can solve the difficult cases, since, according to the literature, the MPNST shows only focal weakly TLE-1 positivity instead of diffuse and strong ones seen in synovial sarcoma, and it is usually cytokeratin 7/19 negative [8]. The gene discussed is TLE1; the disease is malignant peripheral nerve sheath tumor.