A Case of Subcutaneous Myxoid Leiomyosarcoma Misdiagnosed as a Benign Tumor

[email protected] Introduction Leiomyosarcoma is a rare sarcoma that usually originates in the retroperitoneum, thus often occurring in the uterus. It more rarely originates intramuscularly in the peripheral somatic soft tissue. Myxoid leiomyosarcoma, in which the myxoid stroma occupies more than 50% of the tissues, is also rarely reported as the myxoid variant of leiomyosarcoma. The previously reported cases of myxoid leiomyosarcoma of the limb originated in the deep soft tissues or intramuscularly, the size varied from 6 to 29 cm, and they were treated through a wide excision, without misdiagnosis. The authors, however, report herein a case with the performance of intraoperative marginal resection under misdiagnosis as a benign complicated cystic mass via ultrasound, and adjuvant radiotherapy was additionally done after the operation. This uncommon malignant tumor, which was misdiagniosed as a benign tumor, is very rarely reported all over the world.