74-year-old man presents with 0.6cm nodule on the posterior upper arm skin . Pathology showed atypical spindle cell neoplasm, favoring pleomorphic leiomyoma. Wide local excision was performed.
Leiomyoma is a tumor of smooth muscle cells. Leiomyoma of the skin usually arises from the arrector pili muscle of the hair follicles. The extent of atypia determines whether the tumor is classified as a leiomyosarcoma. It can also arise from vascular smooth muscle cells where the metastatic risk is increased, especially with more atypical lesions.
Complete patient evaluation is necessary to evaluate for multiple leiomyomas. This phenomenon is a part of a familial disorder associated with renal cell carcinoma and uterine fibroids.
The treatment of benign leiomyomas is by a complete excision. In our patient, 7mm margins were used to achieve that goal.