Cutaneous leiomyosarcoma with myxoid alteration arising in a setting of multiple cutaneous smooth muscle neoplasms

Background:  Cutaneous leiomyomas and leiomyosarcomas are rare tumors that originate from the arrector muscle of hair follicles or the smooth muscle of blood vessels. Case report:  A 74‐year‐old male presented with a single, erythematous nodule on the left upper arm. This lesion developed within the excision scar of a piloleiomyoma that had been excised 3 years ago. Additionally, physical examination revealed a tender nodule on the right ear. Results:  Histological examination showed a cutaneous leiomyosarcoma with myxoid alteration on the upper arm and an angioleiomyoma on the right ear. Conclusion:  Myxoid leiomyosarcomas have exclusively been reported in the uterus and gastrointestinal tract, but not in the skin. Here, we describe a case of cutaneous leiomyosarcoma with myxoid alteration that developed in the excision scar of a piloleiomyoma and was accompanied by a cutaneous angioleiomyoma in a different location.