Cutaneous leiomyosarcoma on the trunk.

Cutaneous leiomyosarcoma is a relatively uncommon tumor that accounts for 7% of all soft tissue sarcomas. It occurs more frequently in males between 50-70 years and only 10-15% of cases are located on the trunk. Radiotherapy and previous trauma have been implied as risk factors. We report the case of a 57 year-old male with an eight-month history of a hard painless erythematous-violaceous tumor on the presternal region. Histopathology evidenced a malignant spindle cell tumor, "cigar" shaped, with pleomorphic nuclei and a high mitotic index that occupied the entire dermal thickness. Immunohistochemical staining of the tumor cells was positive for smooth muscle actin, desmin and vimentin and negative for S-100 protein and pan-cytokeratin, which supported the diagnosis of dermal leiomyosarcoma. Radical surgery was performed to remove the tumor.