Cutaneous leiomyosarcoma is a relatively rare tumor accounts for about 2-3% of superficial soft tissue sarcomas. It occurs more frequently in males in fifth and sixth decades with a predilection for extremities. We report a 27 years old male with cutaneous leiomyosarcoma of thigh, previously diagnosed as pleomorphicfibroma. The tumor composed of pleomorphic spindle shaped cells with blunt ended nuclei and high mitotic activity. Smooth muscle actin was positive. In this case, the young age of the patient and previous misdiagnosis of the tumor are interesting. Subtle histologic features of low grade leiomyosarcoma can be a pitfall in diagnosis and so affects the optimal management of the patient as it occurred in previous sample of this case.