Primary Cutaneous Leiomyosarcoma of the Lower Extremity: A Case Report and Literature Review.

Cutaneous leiomyosarcoma is a rare soft-tissue sarcoma that appears non-specific clinically and often is misdiagnosed as squamous cell carcinoma. We report the case of a 59-year-old Caucasian male with a grade I leiomyosarcoma tumor on his lower extremity with no previous history of local trauma. The tumor is composed of highly atypical spindle cells with pleomorphic nuclei and mitotic activity on hematoxylin and eosin stains. The diagnosis is confirmed with immunohistochemistry staining positive for smooth muscle actin, vimentin, and desmin. Due to high recurrence rates, the prognosis for leiomyosarcomas remains poor and requires close follow-up to prevent progression.