Secondary Leiomyosarcoma of the Lower Limb Following Uterine Smooth Muscle Tumor of Uncertain Malignant Potential

INTRODUCTION: This report presents uterine smooth muscle tumors of uncertain malignant potential course with an unpredictable clinical behavior and late metastases. Metastases have been described to the humerus, lung, and peritoneum. CASE PRESENTATION: Hereby we present the case of a 71-year-old woman with a past surgical history of hysterectomy and bilateral adnexectomy due to a smooth muscle tumor of unknown malignant potential, who was evaluated 6 years later after the appearance of a mass in the proximal third of the right lower limb. The mass was diagnosed as a G1 epithelioid leiomyosarcoma and was surgically removed with immediate reconstruction with a tendinous transfer to the tibialis posterior muscle to maintain foot dorsiflexion. CONCLUSION: Patients diagnosed with smooth uterine muscle tumors of uncertain malignant potential should be closely followed up given the possibility of recurrence and late metastases, bearing in mind uncommon locations as well, such as the lower limb.